铜/钛合金电子束焊接工艺优化

Investigation on process optimization of Cu Ti electron beam welding

关键词:  QCr0.8合金  TC4合金  电子束焊  工艺优化

Key words:  QCr0.8 alloy  TC4 alloy  electron beam welding  process optimization

摘要:

研究了QCr0.8/TC4电子束焊接工艺及接头组织,由于铜合金热导率高而熔化量较小,以及焊缝中生成大量脆性金属间化合物相,因此对中焊时接头强度较低。采用偏铜侧进行非对中电子束焊接,接头抗拉强度随偏束量的增大而增高,偏束量为0.8mm时接头最高抗拉强度为270.5 MPa。断裂发生在TC4侧熔合线处,为脆性准解理断裂特征。偏铜焊时接头成形得到改善,焊缝包括熔合区及TC4侧反应层两部分。熔合区主要由铜基固溶体组成,硬度较TC4母材有所降低。反应层成分过渡较大,含有多种金属间化合物相。随着工艺参数的变化,反应层厚度也发生变化,从而对接头性能产生影响。

Abstract:

QCr0.8 TC4 electron beam welding process and the structure of joints were studied.The melting quantity of Cu alloy was lower due to its high thermal conductivity;moreover, there were lots of brittle intermetallic compounds in the weld, so the tensile strength of the joint was low.The non-centered electron beam welding was used to improve the tensile strength of Cu Ti joints.It was indicated that the tensile strength was increasing as the lateral deviation quantity increasing, and the maximum value, 270.5 MPa was obtained when the lateral deviation quantity was 0.8 mm.The fracture occurred near TC4 side, and it was quasi-cleavage crack.The weld was consisted of fusion zone and reaction layer near TC4 side. The fusion zone was mainly consisted of Cu-based solid solution with lower hardness than TC4.In the reaction layer, the component transition was obvious, and there were lots of intermetallic compounds. The thickness of the reaction layer was changed as the process parameter being varied, which influenced the mechanical properties of the joint.