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
魏文逸1
作者信息
- 1. 辽宁开放大学辽宁装备制造职业技术学院,辽宁沈阳 110034
- 折叠
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.
Abstract
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 primary α phase and βphase,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 ℃ and aging,the primary α-phase content decreases,the tip dissolution effect is obvious,the microstructure is mainly composed of short rod-shaped α-phase and precipitates of fine needle-like secondary α-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 ℃ respectively,the primary α-phase content is further reduced,the tip dissolution phenomenon is further enhanced,and the primary equiaxed α phase appears,the secondary α phase 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 secondary α phase decreases,the resistance to plastic deformation becomes stronger,and the strain difference between the secondary α phase and the β matrix 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Key words
Ti-5321 alloy/laser deposition manufacturing/heat treatment/microstructure/properties/fracture mechanism引用本文复制引用
基金项目
2021年度辽宁省教育厅高等学校基本科研项目(青年项目)(LJKQZ2021160)
出版年
2024
NETL
NSTL
万方数据