固溶温度对亚稳β钛合金Ti-4Mo-6Cr-3Al-2Sn的组织和拉伸性能的影响  

Effect of Solution Temperature on Microstructure and Tensile Properties of a Metastable β-Ti Alloy Ti-4Mo-6Cr-3Al-2Sn

作　　者：王鹏宇 张浩宇 张志鹏[1] 孙杰[2] 谢广明[2] 程军[3] 陈立佳[1] WANG Pengyu;ZHANG Haoyu;ZHANG Zhipeng;SUN Jie;XIE Guangming;CHENG Jun;CHEN Lijia(School of Materials Science and Engineering,Shenyang University of Technology,Shenyang 110870,China;State Keyj Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;Northwest Institute for Non-ferrous Metal Research,Shanxi Key Laboratory of Biomedical Metal Materials,xi'an 710016,China)

机构地区：[1]沈阳工业大学材料科学与工程学院,沈阳110870 [2]东北大学轧制技术及连轧自动化国家重点实验室,沈阳110819 [3]西北有色金属研究院陕西省医用金属材料重点实验室,西安710016

出　　处：《材料研究学报》2020年第6期473-480,共8页Chinese Journal of Materials Research

基　　金：东北大学轧制技术及连轧自动化国家重点实验室开放课题(2018RALKFKT010);辽宁省自然科学基金指导计划(20180550998)。

摘　　要：对自主设计的新型亚稳β钛合金Ti-4Mo-6Cr-3Al-2Sn(%,质量分数)在不同温度进行固溶和固溶时效处理,观察其显微组织和测试室温拉伸性能。结果表明:随着固溶温度的提高固溶态组织中的初生α相减少,当固溶温度高于相变点后初生α相完全消失,几乎全部为明显长大的粗大β晶粒。固溶温度为900℃的固溶态合金具有良好的强度和塑性匹配,屈服强度为898.7 MPa、抗拉强度为962.5 MPa、断裂伸长率为12.7%。在不同温度固溶处理的时效态合金,均析出了细小的次生α相。固溶温度低于相变点时,在初生α相间析出的细小次生α相呈60°或者平行交错排列;固溶温度高于相变点时初生α相几乎完全消失,随着固溶温度的提高析出的次生α相片层间距变大并粗化。在所有固溶温度下,时效态组织中沿原始β晶界处均析出了连续的晶界α相,合金的塑性均较差。经过750℃/0.5 h固溶和500℃/4 h时效的合金具有良好的强度和塑性匹配,其抗拉强度为1282 MPa,屈服强度为1210.6 MPa,断裂伸长率为5.3%。Plates of a novel metastable β-Ti alloy Ti-4 Mo-6 Cr-3 Al-2 Sn(mass fraction,%) were solid solution treated at different temperatures for 0.5 h and subsequently aging treated at 400℃ for 4 h. Then the microstructure and room temperature tensile properties of the treated plates were examined by means of SEM, TEM and electronic universal testing machine. Results show that the primary α-phase decreases gradually with the increase of solution temperature. When the temperature rises above the phase transformation point the primary α-phase disappears completely, whilst almost all the plates present the microstructure of coarse β-grains, and the β-grains grow obviously. The 900℃ solution-treated plate presents good compromise in strength and plasticity with yield strength 898.7 MPa, tensile strength962.5 MPa, and elongation at break 12.7%. Fine secondary α-phase precipitates occurred for the aged plates after solution treated at different temperatures. When the solution temperature is lower than the transformation point, the secondary α-phases are arranged in parallel or at a 60-degree inclination to the primary ones. When the solution temperature is higher than the phase transformation point, the primaryα-phase almost disappeared, the precipitated secondary α-phase became coarser with larger spacing.Continuous chain of α-phases precipitated along the original β-grain boundaries in the aged plates, which were subjected to solution treatment in the temperature range 700~900℃, and the plasticity of the alloy is poor at the same time. After a combination solution and aging-treatment of 750℃/0.5 h plus 500℃/4 h,the alloy plate exhibits good compromise in strength and plasticity with tensile strength 1282 MPa, yield strength 1210.6 MPa, and the elongation at break 5.3%.

关 键 词：金属材料 亚稳Β钛合金 不同固溶温度 室温拉伸性能 次生α相 

分 类 号：TG146.23[一般工业技术—材料科学与工程] TG166.5[金属学及工艺—金属材料]