TC4-DT钛合金片层组织疲劳裂纹扩展速率  

Fatigue Crack Propagation Rate of Lamellar Microstructure for TC4-DT Titanium Alloy

作　　者：郭萍[1] 赵永庆[1] 曾卫东[2] Guo Ping Zhao Yongqing Zeng Weidong(Northwest Institute for Nonferrous Metal Research, Xi＇an 710016, China Northwestern Polytechnical University, Xi＇an 710072, China)

机构地区：[1]西北有色金属研究院,陕西西安710016 [2]西北工业大学,陕西西安710072

出　　处：《稀有金属材料与工程》2016年第11期2937-2941,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51471136);中法国际合作项目(2015DFA51430)

摘　　要：主要讨论了TC4-DT钛合金不同片层结构的疲劳裂纹扩展速率。试验通过几种不同的热处理工艺获得不同的片层组织结构参数,深入研究了片层组织结构参数对疲劳裂纹扩展速率的影响规律,并对裂纹扩展断口进行分析。结果表明:双重处理空冷条件获得细片层组织较炉冷条件获得粗片层组织具有较高的疲劳裂纹扩展阻力;多重热处理由于获得的次生α片层,导致不同阶段裂纹扩展机理与双重处理的不同。在相同的第一重处理条件下,多重处理在中速扩展区的裂纹扩展速率较双重处理的高。由于次生α片层组织具有较好的变形协调性,加快裂纹的扩展,因此具有较双重空冷处理较高的疲劳裂纹扩展速率。The fatigue crack propagation rates of different lamellar microstructures in TC4-DT titanium alloy were studied. Different lamellar microstructures were obtained by different heat treatment processes, and the effect of lamellar microstructure parameters on fatigue crack growth rate was investigated. Results show that the thin lamellar microstructure by duplex treatment and air cooling possesses a higher fatigue crack propagation resistance than the coarse lamellar microstructure by furnace cooling. The crack propagation mechanism of multi-heat treatment is different from that of the duplex heat treatment, since the multi-heat treatment generates secondary α lamellar. Under the same first heat treatment, the crack propagation rate in a mid-rate range by multi-heat treatment is higher than that by the duplex heat treatment. The secondary α lamellar microstructure has good deformation compatibility, and accelerates the crack propagation; as a result, the multi-heat treatment causes a higher fatigue crack propagation rate than the duplex heat treatment＋air cooling.

关 键 词：TC4-DT钛合金 片层组织 疲劳裂纹扩展速率 疲劳裂纹扩展断口 

分 类 号：TG146.23[一般工业技术—材料科学与工程]