摘要
采用激光焊焊接Ti-3Al-6Mo-2Fe-2Zr(wt.%)β钛合金,研究热处理对接头显微组织和拉伸性能的影响。由于激光焊接的冷却速率可达553 K/s,远大于β相向其他物相转变的临界冷却速率,所以焊缝显微组织由柱状晶形态的单一β相构成。在近热影响区,初生α相和次生α相均转变为β相,且β相晶粒尺寸增大;在远热影响区,尺寸较大的初生α相得以保留。780℃/1 h/WQ热处理后,焊缝中生成厚度约为150~350 nm、长度约为1~3μm短棒状α相,焊接头强度和延伸率有所提高;780℃/1 h/WQ+500℃/6 h/FC热处理后,焊缝中生成厚度约为30~40 nm,长度约为150~300 nm的α相,接头强度进一步提高,但断裂发生在弹性变形阶段。
Laser welding was used to weld Ti-3Al-6Mo-2Fe-2Zr(wt.%) β titanium alloy to study the effect of heat treatment on the microstructure and tensile properties of the joint. Since the cooling rate of laser welding can reach 553 K/s,which is much greater than the critical cooling rate for the transformation of β phase to other phases,the microstructure of the weld is composed of a single β phase with columnar crystals. In the near-heat-affected zone,both the primary α-phase and the secondary α-phase transform into β-phase,and theβ-phase grain size increases;in the far-heat-affected zone,the larger primary α-phase remains. After the 780 ℃/1 h/WQ heat treatment,α phase with the thickness of 150 ~350 nm and length of 1 ~3 μm is formed in the fusion zone. Both the strength and elongation-to-failure of the joints increase after the 780℃/1 h/WQ heat treatment. After the 780 ℃/1 h/WQ+500 ℃/6 h/FC heat treatment,α phase with the thickness of 30~40 nm and length of 150~300 nm is formed in the fusion zone. The strength of the joints is further improved with fracture in tensile deformation stage.
作者
张可召
何超威
戚宋歌
包晔峰
牛红志
严春妍
HANG Kezhao;HE Chaowei;QI Songge;BAO Yefeng;NIU Hongzhi;YAN Chunyan(College of Mechanical and Electrical Engineering,Hohai University,Changzhou 213022,China;School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China)
出处
《电焊机》
2020年第12期59-64,I0006,共7页
Electric Welding Machine
基金
国家自然科学基金资助项目(51804097,51879089)
中央高校基本科研业务费专项资金(B200202219)
常州市科技计划(CJ20190049)。
关键词
激光焊接
Β钛合金
热处理
组织性能
laser welding
βtitanium alloy
heat treatment
microstructure and property