DD32单晶高温合金过渡液相扩散连接

Transient Liquid Phase Diffusion Bonding of DD32 Single Crystal Superalloy

为了提高DD32单晶高温合金过渡液相(TLP)扩散焊接头的力学性能,采用扫描电镜(SEM)和能谱分析仪(EDS)研究接头微观组织,TLP扩散焊过程中基体组织的变化,以及持久过程中基体组织的变化。结果表明,接头由连接区和基体区所组成,未发现明显的扩散区特征。连接区由等温凝固区和残余液相区组成。TLP扩散焊过程对基体组织有重要影响,接头需进行焊后热处理。此外,在持久过程中基体内产生了N型筏。控制TLP扩散焊接头内晶界的形成,可以有效提高接头力学性能。

Microstructure of transient liquid phase（TLP） diffusion bonding DD32 single crystal superalloy joint,microstructural evolution of the parent material during TLP diffusion bonding and stress-rupture has been investigated using scanning electron microscopy（SEM） and energy-dispersive spectrum（EDS） for improving mechanical properties of joint.The results show that the joint contains bonding zone and parent material zone.The diffusion zone is hardly visible.The bonding zone contains isothermal solidification zone and residual liquid zone.Effect of TLP diffusion bonding on the microstructure of the parent material is very important.Therefore,the joints needed postweld heat treatment.Besides,N-type rafts were formed in the parent material during stress-rupture.The mechanical properties of the joint could be effectively improved by restraining formation of grain boundary in the TLP diffusion bonding joint.