Prediction and Simulation of Microstructure of Ti-15-3 Alloy

Ti-15-3 alloy is a new metastableβ-type titanium. The influence of hot deformation parameters on the microstructureof Ti-15-3 alloy after solution treatment has been studied by isothermal compression tests as well as quantitativemetallographic analysis.     

Ti－15－3合金管材的试制及组织性能研究

本文介绍了Ｔｉ－１５－３合金管材的加工工艺及工艺性能，研究了热处理条件对其性能的影响，并分析观察了不同状态下的组织特征。实验中还利用Ｘ射线衍射方法对Ｔｉ－１５－３合金管材的织构类型进行了确定。     

Ti－15－3合金的性能数据

研究了可冷成形的Ｔｉ－１５－３高强钛合金两种时效制度的全面力学性能，为该合金的扩大应用提供了依据。     

Ti－15－3钛合金的应用研究

研究了冷加工对Ｔｉ－１５－３合金时效性能的影响，并研究了该合金的冷成形性能及零件制造工艺，为Ｔｉ－１５－３高强钛合金钣金零件的应用提供了经验。     

铸造Ti-1 5-3合金的凝固行为及组织分析

应用所设计的阶梯铸件的铸型,以及钨铼热电偶和由ADAM系列A／D数据采集及转换模块构成的计算机多通道温度数据采集处理系统,对Ti-15-3合金凝固冷却温度变化进行了实验测试与数据处理,测试了合金的浇注温度,液相线温度和固相线温度,得出合金的凝固温度区间为71℃,对合金阶梯铸件的补缩冒口进行宏观形貌观察表明：Ti－5－3高强钛合金的凝固呈集中补缩的特征,且孔洞内表面光滑,凝固组织观察表明：由于受金属铸型内壁激冷作用和铸件尺寸较小的影响,合金在接近铸型内壁或铸件尺寸较小部位处的铸态晶粒组织较细小,且出现较多黑色第二相的非平衡凝固组织。     

Ti－15－3钛合金的成分控制及性能研究

研究了铝和氧对Ｔｉ－１５－３钛合金的力学性能和冷成形性能的影响，提出了该合金的成分控制范围，为该合金的工业化稳定生产提供了依据。针对我国的国情，提出了与３０ＣｒＭｎＳｉＡ结构钢等强度的时效制度，并研究了相应的力学性能。     

Ti-6-22-22S合金大棒的显微组织与力学性能

研究了6种热处理制度对Ti—6—22—22S合金棒材显微组织和力学性能的影响。结果表明，该合金锻态为细网篮组织，在接近相变点温度固溶并经低温时效后，得到杂乱网蓝组织 少量初生等轴α或晶界条状α的混合网篮组织，三重热处理后得到针状网篮组织。选择适当的热处理制度，可以得到较佳的综合性能。     

变形温度对TA15合金组织和性能的影响

研究了变形温度对原始坯料为片状组织的TA15合金显微组织和性能的影响.随着变形温度(1030～930℃)的降低,合金的室温抗拉强度、延伸率及断面收缩率均增加.β区变形的镦粗试样为片状组织,在剧烈变形区和自由变形区,1080℃变形时β晶粒的动态再结晶程度比1030℃高.两相区变形镦粗试样的显微组织为过渡型组织,难变形区和剧烈变形区及自由变形区组织差别较大.     

航空紧固件用Ti-5553合金的组织和性能

采用扫描电镜和透射电子显微镜研究不同热处理制度对Ti-5553高强钛合金显微组织与力学性能的影响。结果表明:在(α+β)两相区进行固溶处理时,随着固溶温度的升高,Ti-5553合金组织中的初生α相含量逐渐减少,β相的尺寸和体积分数均增加,合金强度逐渐降低。时效后β基体发生转变,晶界和晶内析出大量次生α相。次生α相的尺寸对力学性能产生重要影响,随着时效温度的升高,次生α相逐渐粗化,导致抗拉强度逐渐下降。1240MPa级航空紧固件用Ti-5553的固溶温度应选择Tβ以下,使组织中留有足够的β相,从而时效时在β相中有大量次生α相析出,获得需要的高强度。同时,保留一定含量的初生α相,以便获得良好的塑韧性。经810~820℃,1.5h,水淬+510℃,10h,空冷热处理后,合金可以获得较好的综合性能,抗拉强度达1500MPa,伸长率达14.8%,断面收缩率为38.6%。固溶和时效态的拉伸断口均存在大量韧窝,材料具有良好的塑韧性。     

Ti-15-3钛合金超塑行为研究

为系统了解Ti-15-3合金的超塑性,研究了固溶态和两种不同变形量冷轧态的Ti-15-3合金板材在700～800 ℃和1×10-4 ～3×10-3s-1应变速率范围内的超塑性行为.结果表明:Ti-15-3合金具有较好的超塑性能,冷轧态合金的延伸率均优于固溶态,且随着板材冷轧变形量的增大而增大;各应变速率下,该合金都在780 ℃时获得最大延伸率和应变速率敏感性指数.在780 ℃和1×10-4s-1条件下拉伸时,冷轧变形量为52%的Ti-15-3合金板材获得了370%的延伸率,m值为O.56;变形温度和速率对合金的超塑性能影响很大,合金的延伸率在730～780 ℃范围内随温度的升高和应变速率的降低而升高,合金的流变应力则随之下降.     

Ti-10V-2Fe-3Al合金热变形的研究

利用Gleeble3500热模拟试验机对Ti-10V-2Fe-3Al合金两种状态在不同变形温度及不同变形速率条件下的热变形行为进行了研究。结果表明，不同初始状态对合金的应力应变行为影响较大，经过固溶处理后在低于相变点变形时合金的流变应力比较高，但在高于相变点变形时流变应力没有明显差异；合金的应力指数与合金的状态和应变速率有关，大概以0．1s^-1为界分为低应变速率和高应变速率两部分；合金的表观激活能与材料的状态、变形温度及变形速率有关。当两种状态下的合金在温度为650～800℃、应变速率为0．001～0．1s^-1范围内变形时，β相内只发生动态回复，而α相除了发生动态回复外还可能发生动态再结晶；合金在相变点以上变形时只存在着单一的动态回复机制。     

Thermomechanical Behavior of Ti-6Al-4V Alloy

Ti-6Al-4V, among the Ti alloys, is the most widely used. In the present work, the behavior of Ti-6Ak-4V alloy has beeninvestigated by the uniaxial hot isothermal compression tests and a series of dilatometric experiments were also carried out todetermine the transformation temperatures at different cooling rates. Specimens for hot compression tests were homogenizedat 1050℃ for 10 min and then quickly cooled to different straining temperatures from 1050 to 850℃. Cooling rates were chosenfast enough to prevent high temperature transformation during cooling. Compression tests were conducted at temperaturesfrom 1050 to 850℃ in steps of 50℃ at constant true strain rates of 10~(-3) or 10~(-2) s~(-1). The apparent activation energy forcompression in two-phase region was calculated 420 kJ·mol~(-1). Partial globularization of cr phase was observed in the specimendeformed at low strain rates and at temperatures near the transformation zone and annealed after deformation.     

变形温度和变形程度对Ti－31合金性能和组织的影响

通过高温和室温拉伸试验，研究了变形温度和变形程度对Ｔｉ－３１合金板材性能和组织的影响。结果表明，合金在７５０～８５０℃的温度下变形５％～２０％空冷后，其室温机械性能均能达到材料的技术指标要求。并发现了材料在９００℃的临界变形区。     

变形温度和变形程度对Ti－31合金性能和组织的影响

通过高温和室温拉伸试验，研究了变形温度和变形程度对Ｔｉ－３１合金板材性能和组织的影响。结果表明，合金在７５０～８５０℃的温度下变形５％～２０％空冷后，其室温机械性能均能达到材料的技术指标要求。并发现了材料在９００℃的临界变形区。     

热处理工艺与Ti-3Al-5Mo-5V钛合金显微组织间的定量关系

从钛合金α片的长度、宽度以及长宽比等显微组织特征的统计分析入手,系统、定量地探讨了热处理工艺对于Ti-3Al-5Mo-5V钛合金显微组织的影响规律.结果表明,Ti-3Al-5Mo-5V钛合金显微组织对退火温度的变化较为敏感,在一定温度范围内,退火温度的升高或退火时间的延长,将引起片状α晶粒发生规律性演变,在800℃退火,显微组织有转变为魏氏组织的趋势,在820℃退火时显微组织极易变为魏氏组织.     

Fatigue damage evolution in SiC fiber-reinforced Ti-15-3 alloy matrix composite

Tension-tension fatigue damage behavior of an unnotched SiC (SCS-6) fiber-reinforced Ti-15-3 alloy matrix composite at room temperature was examined, applying maximum stresses of 450, 670 and 880 MPa with R = 0.1. The change in stress-strain hysteresis curves was measured. Fiber fracture behavior and matrix cracking behavior were observed in situ and the results were compared with the change of unloading modulus obtained from the hysteresis curves. The fiber fracture behavior inside the specimen was also determined by dissolving the Ti alloy matrix. The results showed abrupt reductions in the unloading modulus of the composite at stresses of 450, 670 and 880 MPa; the normalized unloading modulus decreased by 8%, 12% and 17%, respectively, in the initial stage (N 10 cycles). This reduction was caused by the multiple fiber fragmentation. Thereafter, the unloading modulus maintained a nearly constant value; and non-propagating matrix cracks were initiated adjacent to the end of fractured fiber. The propagation of the matrix crack again led to a rapid reduction of the unloading modulus, and the composite then failed. With higher applied stress, the fatigue life was reduced. The fracture behavior of the composite was discussed with special attention to the fiber fracture behavior and its effect on the modulus of the composite.     

固溶温度对Ti-5Mo-5V-2Cr-3Al钛合金棒材组织和性能的影响规律

研究了固溶温度对Ti-5Mo-5V-2Cr-3Al钛合金棒材显微组织和力学性能的影响。结果表明,钛合金固溶处理温度在相变点以下,空冷后,显微组织由β相、初生α相以及次生α相组成。随着固溶温度的升高,显微组织中β相晶粒尺寸增大,晶界α相厚度减小,产生有序化现象,而次生α相数量和尺寸减小,使合金的强度降低,塑性升高,但固溶处理温度为800℃时,网状晶界α相使塑性迅速下降;当固溶处理温度在相变点以上,Ti-5Mo-5V-2Cr-3Al钛合金重新形核并长大,随着固溶温度的升高,β相晶粒尺寸增大,初生α相数量减少,强度和塑性都下降,过冷β相晶粒发生应力诱发马氏体现象。     

基于TiH2原料的粉末冶金Ti-6Al-3Nb-2Zr-1Mo合金的组织与性能研究

目的 研究烧结工艺对Ti-6Al-3Nb-2Zr-1Mo合金组织演变及力学性能的影响.方法 以TiH2粉末为原料,采用粉末冶金工艺制备低成本高性能的Ti-6Al-3Nb-2Zr-1Mo合金,分析合金在不同烧结条件下组织与性能的变化规律.结果 TiH2的脱氢温度区间集中在450～700℃;Ti-6Al-3Nb-2Zr-1...     

热处理对铸造Ti15-3合金显微组织和力学性能的影响

借助光学显微分析、ＴＥＭ和ＳＥＭ分析手段研究了不同热处理工艺对Ｔｉ１５－３合金显微组织和力学性能的影响。结果表明：合金在铸态时的组织特征为粗大的β相,由于合金中没有析出相的弥散强化作用,因而合金的强度低,在不同温度时效处理后,在晶内和晶界析出α相,随着时效温度和时效时间的增加,析出相不断粗化,与铸态相比,合金时效后强度大幅度提高而处伸率大幅度下降,在变形过程中,合金中的位错在析出相周围形成缠结,合     

Microstructure and Mechanical Properties of Electron Beam Welded Titanium Alloy Ti-6246

Electron beam welding(EBW) was applied to a 10-mm-thick plate cut from Ti-6246 compressor disk.The microstructural characteristics, microhardness and room temperature tensile properties were investigated. Microstructure observations indicated that there existed plenty of thin needle-like α platelets studding in the matrix of the columnar β grains in the as-welded fusion zone(FZ). Post-weld heat treatment(PWHT) led to the precipitation of small secondary α platelets in the β matrix in heat affected zone and FZ. The thickness and the density of α platelets increased as the temperature of PWHT increased from545 to 645°C. The microhardness across the Ti-6246 EBW joint exhibited a nonuniform distribution. The hardness increased with the decrease of distance to the weld center, and reached the maximum of 467 HV in FZ when PWHT was carried out at 595°C. All the weldments tested with tension were fractured at the base material(BM) and exhibited a ductile fracture mode. The major deformation barrier in BM was the platelet α/β interfaces, however, the major deformation barrier in FZ was found to be β grain boundaries and secondary α/β interfaces. The BM with thicker platelet α phases had lower strength than the other two zones in the joint, and the BM deformed first and led to fracture in this zone.