锻造工艺对新型低成本钛合金组织和性能影响  

Influence of Forging Process on Microstructure and Mechanical Properties of a New Low-Cost Titanium Alloy

作　　者：费跃[1] 朱知寿[1] 王新南[1] 李军[1] 商国强[1] 祝力伟[1] 

机构地区：[1]北京航空材料研究院,北京100095

出　　处：《稀有金属》2013年第2期186-191,共6页Chinese Journal of Rare Metals

基　　金：国防基础科研计划项目(A0520110059)资助

摘　　要：研究准β锻造工艺和两相区锻造工艺对新型低成本Ti-Al-Mo-Cr-Zr系钛合金显微组织和力学性能的影响规律。采用金相显微镜(OM)观察新型低成本钛合金不同锻造工艺后的退火态组织特征,采用扫描电镜(SEM)分析合金的断口形貌,并测试合金的拉伸性能、断裂韧度等主要力学性能。结果表明:合金采用两相区锻造工艺(895℃),获得双态组织,β基体上均匀分布着约占40%的等轴初生α相;合金的强度和塑性较高,其中抗拉强度σb=1054 MPa,延伸率δ5=17%,断面收缩率ψ=51%;但断裂韧度偏低,KIC=63 MPa(1/2)m。采用准β锻造工艺(940℃),获得网篮组织,细小的板条状次生α相交织分布,无初生α相;合金的强度和塑性有所降低,抗拉强度σb=1008 MPa,延伸率δ5=13%,断面收缩率ψ=33%;但断裂韧度较高,KIC槡=86 MPa m。随着锻造温度从两相区895℃升到β单相区940℃,新型低成本Ti-Al-Mo-Cr-Zr系钛合金强度变化幅度小,而断裂韧度、塑性,特别是断面收缩率性能指标对锻造温度变化反应敏感。The influence regularities of quasi-β forging process and α ＋ β forging process on microstructure and mechanical properties of a new low-cost Ti-A1-Mo-Cr-Zr system titanium alloy were studied. Annealed microstructure characteristics of the new low-cost titani- um alloy after different forging processes were observed by means of optical microscope （OM）. The fracture morphologies of alloy were analyzed by means of scanning electron microscope （SEM）. The major mechanical properties such as tensile property and fracture toughness were detected. The results showed that the two-state microstructure could be obtained by α ＋ β forging process （ 895 ℃ ）. The equiaxed primary α phase which was about 40% distributed uniformly in β matrix. The strength and ductility were good. The ulti- mate strength σb was 1054 MPa, the elongation 85 was 17% and the reduction ψwas 51%. But the fracture toughness KIC which was 63 MPa√m was a litter lower. The basket weave microstructure could be obtained by quasi-β forging process. There was the interlea- ving distribution of the fine lathy-shaped secondary α phase in βmatrix, but there was no equiaxed primary α phase. The strength and ductility reduced. The ultimate strength trb was 1008 MPa, the elongation δ 5 was 13% and the reduction ψ was 33%. However the fracture toughness Klc which was 86 MPa√m was higher. The range of strength variation for the new low-cost Ti-Al-Mo-Cr-Zr system ti- tanium alloy was small when the forging temperature changed from 895 to 940 ℃, but fracture toughness and ductility, special for re- duction, were sensitive with the variation of forging temperature.

关 键 词：低成本钛合金 锻造工艺 显微组织 力学性能 

分 类 号：TG146.23[一般工业技术—材料科学与工程]