采用辅助脉冲电流液相扩散连接Ti(C,N)-Al_2O_3的接头形成行为及强度

Joint formation behavior and joint strength of Ti(C,N)-Al_2O_3 ceramic matrix composite bonded by liquid phase diffusion bonding with auxiliary pulse current

采用辅助脉冲电流液相扩散连接方法,对Ti（C,N）-Al2O3陶瓷基复合材料与40Cr钢进行了焊接试验,重点研究了在辅助脉冲电流作用下,界面及焊缝组织演变、基体材料溶解等界面行为,探讨了工艺参数对接头强度及断口形态影响规律.结果表明,通过采用辅助脉冲电流液相扩散连接Ti（C,N）-Al2O3与40Cr钢,可以在较短的焊接时间条件下获得较为稳定的接头强度,四点弯曲平均强度位于231～272 MPa之间;降低焊接件整体加热温度以缓解接头残余应力,控制界面和焊缝化学冶金反应进程以较少金属间化合物数量、提高固溶体含量,抑制活性元素Zr向陶瓷基复合材料中的扩散进程以减少陶瓷颗粒向焊缝中的溶解量,是提升焊接接头强度的关键因素.

The bonding between Ti( C,N)-Al2O3 ceramic matrix composite and 40 Cr steel was conducted using liquid phase diffusion bonding with auxiliary pulse current. The change on interfacial microstructure and dissolution of base materials caused from auxiliary pulse current was researched, and the effect of bonding parameters on joint strength and fracture surface during four-points bending tests were also investigated. The results show that the strength of the resultant joint reached 231-272 MPa with auxiliary pulse current during diffusion bonding in a shorter bonding time. The bonding temperature could be reduced to release the residual stress in the joint,and the interfacial reaction in the joint could also be controlled to decrease the amount of intermetallic compounds and increase solid solution. The diffusion process of active Zr element to ceramic matrix composite materials was suppressed to reduce the amount of ceramic particles dissolved in the weld,which is a key factor to improve the strength of welded joint.