The requirement for titanium materials analysis

Titanium consumption mainly concentrated in the field of aviation industry, accounted for about 50%, in 2011, global titanium production reached 148000 tons, including commercial aviation use about 64000 tons of titanium, the future of global economic growth, the demand for air transport is still huge, is expected to demand about 30000 new aircraft over the next 20 years or so, at the same time, demand for new aircraft to titanium is higher than the old aircraft, we expect that within 20 years commercial aircraft to the titanium demand will reach an average of 40 tons/frame;Accordingly, the next 20 years new global commercial aviation titanium demand of about 1.2 million tons, the compound annual growth rate of about 17%, the average annual 60000 tons of new titanium demand, civil aviation with titanium field presents the fast growth.In addition, military aviation also will appear new opportunities;Tension due to the global geopolitical situation, countries around the world military spending increases, military aviation sector is expected to demand a new blue ocean, represented by making, turned to the fourth generation of the collective global warplanes machine age;And new aircraft with titanium content is much higher than that of aging aircraft, so the future military aircraft upgrades will lead to new requirements. Titaniumcn
1. The titanium consumption mainly concentrated in the field of aviation industry
Around the world (including China and Russia), titanium consumption mainly concentrated in the field of aviation industry, in 2011, the global commercial aviation consumption rate reached 42.6%, to 6.5% military titanium (mainly for military aviation), the proportion of consumption of aviation titanium is close to 50%;Titanium industry consumption ratio is 48.1%, emerging market consumption to 2.8% titanium.
The proportion of consumption of aviation titanium close to 50%, and historically, titanium industry cycle are closely related to changes in temperature and aviation industry.Over the past nearly 40 years, titanium price fluctuations at a time, are mainly caused by the industry's needs change;And commercial air transport industry as the global economic growth is closely related, so the development of titanium industry also reflects the strong cyclical.
2. Titanium demand analysis in the field of civil aviation
Titanium alloy is one of the main structural material of modern aircraft and engine, the structure of titanium alloy to reduce weight, improve the efficiency of the structure, the improvement of structure reliability, increase the body's life, meet the high temperature and corrosion environment has other metal irreplaceable role, its application level become the important indicators of aircraft structure material advanced degree, is one of the important aspects affect the performance of the flight.
In general, the vast market demand in the future aviation has provided a broad space for development of titanium industry.On the one hand, the civil aviation giant aircraft new demand will bring a great boost to the global demand for titanium, over the next 20 years global demand for about thirty thousand of the civil aircraft, laid the solid foundation of titanium requirements;In addition, considering the titanium dosage of new aircraft was obviously higher than that of old aircraft, we expect the next 20 years, as the old plane retired, civilian aircraft the average amount of titanium would increase greatly, we expect the civil aircraft over the next 20 years the average amount of titanium 40 tons/frame, will rise to 30000 civil aircraft over the next 20 years, the new titanium demand of about 1.2 million tons, over the next 20 years of civil aviation titanium demand annual compound growth rate of about 17%.Airbus, and according to the measure of the next decade the world about 13000 new civil aircraft, which calculates the next 10 years, demand for aviation with titanium compound annual growth rate of 22% (assuming that the future ten years civil aircraft with titanium average amount up to 30 tons per frame)

The discovery of titanium and laboratory research

At the end of the 18th century, British priest and amateur mineralogist William Gladstone gore (William Gregor) and German chemist m. h. carat prot (m. h. Klaproth) successively in 1791 and 1795, respectively, from a black magnetite ore (later know this is titanomagnetite) and a kind of non magnetic oxide ore (later understand that it is the natural rutile ore) discovered a new element, they are called "ink," (place) found that titanium magnetite and titanium "soil".Prove a few years later, from these two kinds of minerals found in the so-called "ink," and "Titanium soil" is actually the same kind of element oxide, and in Greek mythology hercules Titan (Titans) to name the new element for "Titanium" (Titanium).
First made from titanium found to relatively pure titanium has experienced 120 years of history.And pure titanium obtained by laboratory for the first time to the first time in industrial production, and spent nearly 40 years.Many researchers have done a lot of exploration, to suffer again and again failed, finally succeeded in 1948, dupont, produce the tonnage level of titanium sponge, porous titanium.
Chinese titanium industry during the 10 years of rapid development, serious out of control, many places in the local protectionism "vigorous" break into the development of titanium project, causing serious oversupply of titanium market, although the titanium and titanium use accelerated, but also can not change the present situation of the actual capacity is more than demand.In 2012, for example, although more than 60000 tons of total titanium significant growth over the previous year, but titanium ingot exports increased significantly, baosteel, treasure titanium titanium processing enterprises titanium ingot stock accumulated in more than 5000 tons, other countries also stockpiled 4000 metric tons of titanium ingots.Thus, domestic titanium production, demand is not synchronous growth, on the contrary, it can be seen that foreign titanium industry development is relatively rational, unlike domestic development "stuttering" in the out of control.
In 2012, the economy starts to recover, the market of titanium industry in China is still weak, but we don't blame it is caused by the financial crisis, the European debt crisis, but in the development of their own out of control to find the reason, otherwise, all kinds of the economic crisis is over, desperately on project development crisis around the titanium industry in China is still there.Throughout the course of the more than 10 years of titanium industry in China is such a along with the cycle of pain: the first expansion - the first reshuffle to increases production for the second time, the second shuffle...Development of titanium industry in China from 1960 s to 2004, both titanium and titanium processing capacity is very small, such as at the end of 2000 China's production of titanium sponge, 2000 tons, but as the titanium demand is gradually increasing, the end of 2004 to 2005 titanium sponge price has risen from $5, 60000 tons up to 200000 ~ 200000 yuan 1 tons, has a price no city phenomenon of sudden huge profits, began to appear quietly in titanium field appeared for the first time large-scale expansion, just a few short years capacity quickly turned over more than 60 times.Expansion, adjustment, pain, 2012 years after the reshuffle sponge titanium in China production base in 2000 increased by more than 40 times

Titanium sponge production technology

Chloride process
Titanium tetrachloride is mainly used for producing titanium sponge and titanium dioxide and titanium trichloride.Its manufacture method are many, mainly include boiling chlorination, molten salt chloride and shaft furnace chloride method.Boiling chlorination is current the main method of producing titanium tetrachloride (China, Japan, the United States USES), followed by the molten salt chloride (commonwealth of independent states (cis) countries have adopted), the shaft furnace chloride has been eliminated.Boiling chlorination is generally low levels of calcium and magnesium rich high-grade titanium material as raw material, and the molten salt chloride can be used with high calcium and magnesium of raw materials.TitaniumCN
Boiling chlorination
Boiling chlorination is rich titanium material of fine particles and the solid carbonaceous reductant (petroleum coke), under the action of high temperature, chlorine gas flow in fluidized state of chlorination reaction, thus making the method of titanium tetrachloride.The law has accelerated gas - solid phase mass transfer and heat transfer process, strengthen the characteristics of the production.Now boiling chloride at home and abroad to use the raw material with high titanium slag, natural rutile, artificial rutile etc.
Molten salt chloride
Molten salt chloride is the fine grinding of titanium slag or suspension in the molten salt, rutile and petroleum coke (mainly composed of KCl, NaCl, MgCl2 and CaCl2) medium, and chlorine gas is piped in, thus making the method of titanium tetrachloride.Generally also can use electrolytic magnesium waste electrolyte, under the condition of 973 k to 1073 k filling the chlorine gas, so the chlorination reaction speed by melt properties, composition, the types of reductant, the nature of the raw material, chlorination temperature, the concentration of chlorine gas and ventilation with speed, melt height, with the influence of factors such as carbon.
Shaft furnace chloride
Shaft furnace chloride will be chlorinated or rutile titanium slag and petroleum coke fine grinding, plus binder blending briquetting and the coking, the briquette made of material stack in vertical furnace chloride, a solid layer of state function of preparing to titanium tetrachloride method with chlorine gas, also known as the fixed layer chloride or mass of chloride, the current basic has been eliminated.
Mg reduction method
Is the essence of the magnesium reduction, in 880 ℃ ~ 950 ℃ under argon atmosphere, let the titanium tetrachloride with magnesium metal reaction of spongy titanium and magnesium chloride, with vacuum distillation to remove magnesium magnesium chloride and excess of titanium sponge, to obtain pure titanium, distillation condensate by recycling molten metal magnesium, magnesium chloride by molten salt electrolysis recycling magnesium and chlorine.Be obtained from the refined titanium tetrachloride titanium, divided into reduction and distillation of two steps.In a long period of time, reduction, distillation is carried out step by step, and now have to joint, large-scale.
Magnesium reduction, distillation process and equipment
Large titanium metallurgy enterprises are titanium magnesium joint enterprise, most manufacturers use reduction distillation integration process.This process is known as joint or half joint, it implements the raw material of Mg - Cl2 - MgCl2 closed-circuit circulation.
Integration of reduction distillation equipment, divided into "U" type and "I" type two kinds.Inverted "U" type equipment is the reduction pot (retort) and condensing tank with valve pipe connections between, establish special heating device, the whole system equipment before reduction assembled at a time."I" type of integration technology of system equipment such as one-time assembled before reduction, called joint method of equipment;And assemble the reduction device first, wait for after reduction, strike and then assembled condensing tank to distill for operation system of equipment it is called a string of joint, middle with magnesium "transitional period" link.

The hardness of the material

Local resistance material hard objects the ability referred to as the hardness of its surface.Test the steel hardness is the most common method is to use file file to wipe on the edge of the workpiece, by its surface scratch depth is presented to determine the hardness of high and low.This method is called file test this method is not scientific.With hardness tester to test more accurate, but also the modern test hardness of the commonly used method.The commonly used hard. Method to measure brinell, rockwell hardness and vickers hardness testing methods, such as hardness is an important measure of degree of hard nd soft metal materials performance metrics, it can be understood as the material the ability of resistance to elastic deformation and plastic deformation or damage, can also be expressed as the material's ability to fight the residual deformation and failure.Hardness is not a simple physical concept, but the material mechanical properties such as elasticity, plasticity, strength and toughness of the composite indicator.Hardness test according to the different test methods can be divided into static pressure method (such as brinell, rockwell hardness vickers hardness, etc.), scratch method (such as mohs hardness), rebound method (e.g., shore hardness) and microhardness, a variety of methods such as high hardness.Brinell hardness to HB [N] (KGF/was) said (HBS \ HBW) production of cloth hardness were determined after the annealing, normalizing and tempering was just a, and cast iron, non-ferrous metals, such as low alloy structural steel wool embryo or hardness of semi-finished products.Rockwell hardness can be divided into the HRA, HRB, HRC, HRD. Four, and their measuring range and application range are also different.As a production of HRC used most frequently.Indentation is small, measurable thinner material, the hardness of hard materials and finished products.Vickers hardness In order to HV said.Metal Hardness (Hardness), code-named H.By different method of hardness test, the conventional said brinell (HB) and rockwell (HRC), vickers's (HL) hardness (HV), etc, among them with HB and HRC is more commonly used.HB has a wide application range, HRC is suitable for the surface of high hardness materials, such as heat treatment hardness, etc.The difference is that a probe different hardness tester, brinell hardness tester measuring head of steel ball, and the measurement of rockwell hardness tester for diamond.HV - suitable for microscopic analysis.Vickers hardness (HV) to 120 kg load and apex Angle of 136 ° diamond square forcer pressure cone into the surface of materials, materials of the indentation indentation surface area divided by load values, i.e., for the vickers hardness (HV) values.HL portable hardness tester, easy to measure, after using the impact ball head impact surface hardness, produce bounce.Using the punch at 1 mm from the sample surface of rebound velocity and the ratio of impact velocity calculated hardness, formula: hardness on the Richter scale = 1000 x VB (rebound)/HL VA (impact speed).A portable hardness tester with magnitude on the Richter scale (HL) measurement can be converted into: after brinell (HB) and rockwell (HRC), vickers (HV), shore hardness (HS).Or directly with measuring principle with cloth's (HB) and rockwell (HRC), vickers (HV), (HL), the shore on the Richter scale (HS) measuring hardness value. 

HB - brinell hardness;Brinell hardness (HB) commonly used for soft materials, such as non-ferrous metal, before or after the annealing heat treatment of steel.Rockwell hardness (HRC) is commonly used in high hardness materials, such as the hardness after heat treatment and so on.

Cloth type hardness (HB) is based on a certain size of test load, to a certain diameter of hardened steel or hard alloy ball pressure into the metal surface to be tested, keep time, and then unloading, measured surface indentation diameter measurement.Cloth type divided by indentation hardness value is a load of spherical surface area of the quotient.Is commonly: at a certain load (3000 kg) usually put a certain size (10 mm in diameter) of a hardened steel ball pressure into the material surface and stay for a period of time, to load, load with indentation area ratio, is the brinell hardness number (HB), the unit is kg force/was (N/was).

Los type is the indentation hardness depth of plastic deformation to determine the hardness value indicators.At 0.002 mm as a unit of hardness.When HB > 450 or sample hours, brinell hardness test and will not be used to switch to rockwell hardness measurement.

The physical properties of the titanium plate

The hardness of the highest quality of industrial pure titanium is generally less than 120 (brinell), and other industrial pure titanium hardness is 200-295 (brinell).The hardness of pure titanium castings is 200-220 (brinell).Titanium alloy under annealing conditions of hardness value is 32 to 38 (calibration) rockwell C, equivalent to 298-349 brinell hardness.As-cast al Ti - 5-2.5 Sn and Ti - 6 al4v hardness is 320 (brinell), Ti 6 al - low void impurities 4 v casting hardness is 310 (brinell).
Titanium plate elastic modulus:
Of industrial pure titanium tensile elastic modulus is 105-109 gpa. Most of the titanium alloy in the back fire conditions of tensile modulus of elasticity, 110-120 gpa.Age hardening of titanium alloy was a little higher than in the annealed condition has tensile elastic modulus, elastic modulus is equal to the resistance may be greater than a stretch elastic modulus.Although the strength of the titanium and titanium alloy is higher than aluminium and aluminium alloy many, but only 55% of the stiffness.Than the elastic modulus of titanium alloy and aluminum alloy flat, after beryllium and molybdenum and some high temperature alloys.The change of industrial pure titanium or shear modulus for 46 gpa.The shear modulus of titanium alloy for 43-51 gpa.
Titanium plate fracture toughness and impact toughness:
Based on types and conditions of titanium alloy, pure titanium charpy notched impact strength of the value of 15 to 54 j/m3, the state of the forging is about 4 to 10 j/m3.The impact strength of titanium alloy in the annealing conditions for 13-25.8 J/m3, less limitation conditions.Forging condition of al Ti - 5-2.5 Sn charpy v-notch impact strength is 10 j/m3, T1-6, 4 V for 20-23 j/m3.The lower the oxygen content of titanium alloy, this value is higher.Many titanium alloy has the very high fracture toughness, perhaps say titanium crack expanding excellent talents.Annealing conditions of Ti - 6 a1-4 v. when, lack of concentration factor/C = 25.4 mm, the notch tensile strength and the notch tensile strength is greater than 1.The strength of the advances in titanium alloy, add the void content of give alloy shock function whammy impact and fracture toughness.
Under normal atmospheric atmosphere, the endurance limit of titanium and titanium alloy processing and annealing is about 50% - 50% of the tensile strength, the gap condition (3.9) 10000000 times fatigue experiments when annealed Ti 6 al 4 v the endurance limit of 20% of the tensile strength.
The strength of the titanium and titanium alloy are divided into tensile strength, bending strength, shear strength and bearing strength.
Tensile strength, the tensile strength of pure titanium is 265-353 mpa, usually titanium alloy is 686-1176 mpa, the most Xie up to 1764 mpa.Titanium alloy with a lot of appropriate strength of steel, but is much better than the intensity of titanium alloy.
Shear strength, shear strength in the titanium and titanium alloy are usually the tensile strength of 60% 70%.
Bearing strength: titanium and titanium alloy sheet strength of confined to about 0.2 to 2.0 times that of the tensile strength.
Tightening strength: titanium and titanium alloy tightening strength is not lower than the tensile strength.Tightening of industrial pure titanium roughly equal yield strength and tensile yield strength, and Ti 6 al 4 v and Ti - 5-2.5 Sn tightening strength was a little higher than the tensile strength.

Titanium materials microstructure test

Titanium materials microstructure directly affects the performance and service life of mechanical parts, metallographic analysis is an important means of internal quality control of mechanical parts.In new materials, new technology, new product research and development, in scientific research to improve the quality of metal products inner, cannot leave the metallographic analysis technology. TitaniumCN
The so-called "phase" is in the alloy has the same chemical composition, structure and even some of the same atomic state of aggregation.There are obvious separate interface between different phase.Alloy are generally consists of the performance of alloy of each structure performance of the phase and phase combination of decision.The alloy phase structure can be roughly divided into two basic types of solid solution and compounds.
The so-called "metallurgical" is metal or alloy phase structure.
Metallographic examination (or metallographic analysis) is the metallography method is applied to check the metal materials of macro and microstructure of the work.
Metallography: narrow sense of metallography, that is, the alloy phase diagram, with the naked eye observation, with the help of a magnifying glass and microscope, the study of metal and alloy organization and phase transformation.
Microstructure is the concrete forms of metals metallographic, such as martensite and austenite and ferrite, pearlite and so on.Microstructure of generalized refers to two or more substances in microscopic state of mixed state and interaction.

Metallographic microscope is the optical microscope technology, photoelectric conversion technology, computer image processing technology together perfectly and developed into a high-tech product, you can easily observe metallographic images on the computer, and analysis of metallographic atlas, rating and output images, such as printing.It is well known that alloy composition, heat treatment, hot and cold processing technology directly affect the internal organization of metal material, the change of the structure, to make the change on the mechanical properties of the parts.Therefore analyzed by metallographic microscope to observe the inspection of metal internal organizational structure is an important means of industrial production.
Metallographic microscope is mainly composed of optical system, lighting system, mechanical system, the attachment device (including photography or other device such as microhardness).According to different tissue samples of metal on the surface composition of light reflection characteristics, with a microscope in the visible light range for these organizations component in the optical research and qualitative and quantitative description.It can display 500 ~ 0.2 m metal group characteristics of the scale.As early as in 1841, the russians (п п. А н с о kind guide) was studied under the magnifying glass decorative pattern on the Damascus steel sword.To 1863, the British (H.C.S orby) petrography of the method, including sample preparation, polishing and rot engraved technology transplanted to the iron and steel research, such as the development of metallurgical technology, went on to make a batch of low magnification metallographic pictures and other organizations.Soapy and his contemporaries (German arjun artens) and French (f. Osmond) of scientific practice, which laid a foundation for modern optical metallographic microscopy.At the beginning of 20th century, improving optical metallographic microscopy, and widely used in metal and alloy microscopic analysis, so far is still a basic technology in the field of metallography.

Metal macrostructure defect inspection

Metal macrostructure defect inspection is also referred to as a macroscopic examination.It is with the naked eye or is not more than 10 times the magnifying glass to check the metal surface, fracture or macroscopic organization method and its defects.Macroscopic examination on the metal ingot casting, casting, forging, welding, rolling, heat treatment process, the commonly used inspection method is a kind of important.This test method is simple, rapid, can reflect the metal macro morphology and distribution characteristics of regional organizations and defects.Enable people to correct and comprehensive judge the quality of the metal material, in order to guide the production, the rational use of materials science.For the analysis of the optical microscopy and electron metallographic basic work.Macroscopic examination including macrostructure and defect inspection (including acid corrosion, sulphur print, tower turning and non-destructive methods such as damage) and fracture analysis, etc. TitaniumCN
1. The typical macroscopic defects
The typical macroscopic defects have segregation, porosity, shrinkage cavity, bubble, crack, low power inclusion, coarse grain ring, etc.
(1) the uneven phenomenon called segregation of alloy chemical composition segregation.Based on the characteristics of the range size and position of the segregation, generally can be divided into three kinds.The intracrystalline partial and segregation, regional segregation, gravity segregation.Coring and segregation as after solid solution alloy casting in the condensation process, due to the solid phase liquid ingredients in constant change, therefore, even within the same crystal, first part of the solidification after solidification of the part and its chemical composition is not the same.The intracrystalline chemicals called coring uneven phenomenon.
(2) the shrinkage and loose in the ingot head, middle, grain boundary and interdendritic, often have some of the macroscopic and microscopic shrinkage holes, collectively known as the shrinkage cavity.Large volume and concentration of shrinkage cavity called on shrinkage cavity;Small and dispersed shrinkage cavity called osteoporosis.Which appear in the grain boundary and interdendritic porosity is also called microporosity.Shrinkage cavity and loose irregular shape, the surface is not smooth, easily distinguished from the more pliable porosity.Ingot casting box segregation four years the national registered construction engineer examination in terms of construction project cost management of construction engineering construction project cost case analysis construction engineering technology and measuring shrinkage and loose the direct cause, is solidified body contraction of the liquid metal solidification occurs.Residual shrinkage cavity in the metal material of axial position of the transverse specimens acid leaching, easy to recognize.
(3) the hole according to the position of porosity in ingot casting, it can be divided into three classes of surface porosity, subcutaneous blowhole and internal porosity.Can be divided into the precipitation type according to the cause of porosity, porosity and reactive pores.
(4) the most complicated composition of crack or higher amount of impurities or have a small amount of non-equilibrium eutectic alloy, there are larger crack tendency.Especially large ingot casting.Under the condition of the cooling strength of continuous casting, the tendency of crack is bigger.Produced in the process of solidification crack is called hot crack.After solidification cracks occurring in the process of cooling is called cold crack.More hot cracking along the grain boundary extension, twists and turns and irregular, often for transgranular crack, cold crack in a straight line extension.
(5) low power inclusions
On the acid leaching at low sample, some naked eye can see fire-proof material, slag and other non-metallic inclusions, these relatively bulky inclusions are called macroscopic inclusions.Them on acid leaching test plate in the form of Mosaic, and maintain its inherent in all sorts of color, common are gray, beige and dark gray, etc.Some low power inclusions may fall off during production, and surface is empty.Empty characteristics different from the edge of the bubble is that it is not neat, spongy.
(6) streamline is the low melting point metal composition and banded structure segregation when rolling or extrusion stretch.At the same time, also in the process of rolling ingot casting grain in elongated into strips.After recrystallization heating process can restore the elongated grain into equiaxed grain, but due to the low melting point elements and the elongation of banded structure is formed by the distribution of stripe still exist.In steel on the longitudinal section after polishing and acid leaching, with the naked eye can see the line of the stripes.The macroscopic organization called fibrous tissue, also known as the streamline.
(7) coarse grain ring is one of the main defects of aluminium alloy extrusion products.Aluminum alloy extrusion in the subsequent heating of the outer coarse grains, according to the phenomenon of coarse grain rings.Its characterization features are: for single-hole extrusion bar, bulky zone, a symmetric circular.The porous squeeze rod eccentric crescent shaped.The presence of coarse grain ring could sharply reduce the mechanical properties.Coarse grain ring also has a "genetic" organization.With coarse grain ring blank after moulding, still keep original coarse grain area, causing uneven and affect the surface quality of molded parts.Even in the heat treatment process is easy to cause crack.Study shows that the formation of coarse grain ring is driven by extrusion deformation caused by uneven friends.
2. The organization and the defect is etching method
Macrostructure etching method is divided into hot acid etching method, cold acid etching method and three kinds of electrochemical corrosion method.Experiments using cold acid etching.Cold acid etching operation main points are as follows:
(1) according to the appropriate material selection type and a certain proportion of etching solution.
(2) on the surface of the sample inspection should finish in 7 above, acid corrosion tests should be surface wipe, remove the oil pollution.
(3) with the method of corrosion, pour acid slowly in the basin of land acid sample again, then acid brush divide evenly with a brush,
(4) etching, water rushs acid, and alkaline neutralization, then use hot water to rinse, blow dry immediately.
3. The fracture analysis of metal fracture according to the fracture methods can be divided into brittle fracture
And thus reduce the grain boundary strength.Transgranular fracture is due to the strength of the grain itself is not high, or along the grain in the process of crystallization of some crystal clip into the impurities.See the shape of the fracture physical objects.Ductile fracture rupture occurred plastic deformation before.Distorted the original grain (spin or broken), no longer keep the original size, shape, and can't study from these fracture metal internal organization.See the shape of the fracture physical objects.

Titanium Phase transition temperature of testing

GR2 industrial pure titanium with good corrosion resistance, mechanical property and welding performance, in ship, chemical industry, and many other fields have important applications.Because the metal under the condition of the machining process must be, its organization status mainly depends on the organization in the process of evolution, heat treatment and strongly influence its performance.High temperature, therefore, the research of industrial pure titanium GR2 organization evolution behavior has important significance.In this paper, using the confocal laser scanning microscope (CLSM), optical microscope (OM), differential scanning calorimetry (DSC) method to study the isometric state of industrial pure titanium GR2 in organization evolution behavior in the process of heating, heat preservation and cooling, analyses and summarizes its organizational evolution law.In heating and heat preservation phase, bending part of alpha grain boundary migration and tend to be straight, short heating effect on alpha grain size is very Titaniumcn small.Temperature at the initial phase transition point T alpha/alpha + beta above multiple parallel "lenticular" in the same alpha beta strip around the intracrystalline nucleation and diffusion mechanism to gobble up alpha growing, with "tent" embossed on the surface of the form.Temperature more than completely alpha + beta phase transition point T/beta, alpha and beta phase change over, initial alpha beta article slices with crystal and to form a "group", continue to heat, the "group" "eat" to each other, eventually become the bulky shaft such as beta.The dynamics of beta grain grew up statistics and fitting calculation.From the state of the different cooling, different organization at room temperature.From the alpha + beta two-phase district cooling, such as organization revert to the original state axis, floating on the surface of convex disappear;From cooling, just completely into beta phase formation interface irregular alpha organizations;From cooling, axis beta groups such as alpha and beta and alpha phase change can be divided into grain boundary westergren alpha two phase nucleation and grain boundary first alpha in beta at grain boundary nucleation and growth to connect into a thin film of grain boundary alpha, then westergren alpha on the grain boundary alpha nucleation, and in the form of a layer of flake cluster to grew up in the beta phase, until full of beta grain, beta and alpha end of shift, forming a typical widmanstatten structure.Cooling rate equivalent shaft beta beta and alpha phase transition in the process of cooling effect is very big, the faster the cooling rate, grain boundary alpha and westergren alpha thickness is smaller, westergren alpha elongation the faster, the faster the phase transition.Under different cooling rate on the grain boundary of alpha broadening, the elongation and the thickness of the westergren alpha, and beta and alpha phase transformation kinetics of quantitative statistics, beta and alpha phase transformation kinetics of empirical formula is given.

Using the calculation method and differential scanning calorimetry and continuous heating metallographic method
Three kinds of method to calculate and determine the two-phase titanium alloy TC11 (alpha + beta)/beta phase transition point.Calculation method for each element and the influence of impurity element content on the phase transformation point value is within the scope of a content calculated value, thus calculated is close to the phase transition point and the measured values;Differential scanning calorimetry because of titanium alloy and chemical reaction of the crucible, produce transformation hysteresis phenomenon, cause the measured phase change temperature is too high;Metallographic method and continuous warming choose smaller due to the quenching temperature interval, measuring accuracy is higher, therefore more accurate measurement of TC11 titanium alloy phase transition temperature.Use the synchronous sTA449c thermal analyzer measurement titanium and titanium alloy phase transition temperature, the reference sample for 23 alo powder, 1 min to 10 ℃ temperature;The protection of argon flow for 45 m11min.Before test, should be first in the two samples in the crucible of 23 alo powder amount, measuring instrument baseline within the rules, can begin formal sample DSC curve.The phase transition temperature was evaluated by continuous heating metallographic method.The sample size to 10 mm x 10 mm x 10 mm;When heating sample to ensure heat through, time of heat preservation for 60 min.Quenching temperature range is 990 ~ 1040 ℃, quenching temperature interval of 10 ℃, and then water quenched sample.Of which the transfer speed of no more than 2 s.After quenching specimen made of metallographic observation, the optical microscope magnification of 500 times the sample organization change.2.1 calculation method according to the phase transition temperature of each element titanium phase transition point of the influence of the phase change temperature calculated formula is: / T + phase transformation point = 885 ℃ + Σ content of each element x (1) the effect of the elements of phase transformation point of the type of 885 ℃ for calculating the phase transition point of pure titanium.