热处理对激光沉积制造Ti-5321近β钛合金组织和性能的影响  

Effect of heat treatment on microstructure and properties of laser deposited Ti-5321 metastable β titanium alloy

作　　者：魏文逸 Wei Wenyi(Liaoning Equipment Manufacturing Vocational and Technical College,Liaoning Open University,Shenyang Liaoning 110034,China)

机构地区：[1]辽宁开放大学辽宁装备制造职业技术学院,辽宁沈阳110034

出　　处：《金属热处理》2024年第9期132-138,共7页Heat Treatment of Metals

基　　金：2021年度辽宁省教育厅高等学校基本科研项目(青年项目)(LJKQZ2021160)。

摘　　要：研究固溶温度对激光沉积制造Ti-5321近β钛合金显微组织与力学性能的影响。结果表明,沉积态Ti-5321合金试样显微组织由板条状的初生α相和β相组成,抗拉强度达到1050 MPa以上,断后伸长率达到4.5%左右,断裂模式为韧脆混合断裂。经770℃固溶时效处理后,初生α相含量下降,尖端溶解作用明显,显微组织主要为短棒状α相,析出细针状次生α相,试样抗拉强度达到1180 MPa以上,断后伸长率达到0.8%左右,断裂模式转变为脆性断裂。固溶温度分别为820℃和870℃时,初生α相含量进一步减少,尖端溶解现象进一步增强,出现等轴状初生α相,次生α相含量增加,试样抗拉强度达到1180 MPa以上,几乎没有塑性。这是因为随着固溶温度的升高,次生α相尺寸减小,抵抗塑性变形能力变强,在外部载荷作用下次生α相与β基体的应变差加大,产生微裂纹,导致塑性变差。Effect of solution treatment temperature on the microstructure and mechanical properties of the laser-deposited Ti-5321 near-βtitanium alloy was investigated.The results show that the as-deposited Ti-5321 alloy specimens consist of lath-like primaryαphase andβphase,with tensile strength above 1050 MPa and elongation after fracture about 4.5%,and the fracture mode is ductile-brittle mixed fracture.After solution treatment at 770 C and aging,the primaryα-phase content decreases,the tip dissolution effect is obvious,the microstructure is mainly composed of short rod-shapedα-phase and precipitates of fine needle-like secondaryα-phase,meanwhile the tensile strength of the specimen is above 1180 MPa,the elongation after fracture is about 0.8%,and the fracture mode is changed to brittle fracture.When the solution treatment temperature is 820℃and 870 C respectively,the primaryα-phase content is further reduced,the tip dissolution phenomenon is further enhanced,and the primary equiaxedαphase appears,the secondaryαphase content increases,meanwhile the tensile strength of the specimen is above 1180 MPa,and there is almost no plasticity.This is because as the solution treatment temperature increases,the size of the secondaryαphase decreases,the resistance to plastic deformation becomes stronger,and the strain difference between the secondaryαphase and theβmatrix increases under external loading,resulting in microcracking and leading to plasticity deterioration.

关 键 词：Ti-5321合金 激光沉积制造 热处理 显微组织 性能 断裂机制 

分 类 号：TG166.5[金属学及工艺—热处理]