GH99合金液相扩散连接界面组织分析

Microstructure analysis of TLP bonded joint of GH99 alloy

采用自制Ni-Cr-Si-B系列中间层对GH99镍基高温合金进行了液相扩散连接(TLP),借助扫描电子显微镜(SEM)、能谱分析仪(EDS)等分析手段研究了焊接工艺参数以及中间层成分变化对接头界面组织的影响.结果表明,随着等温时间和焊接温度的增加,析出化合物的数量减少,接头组织更加均匀.接头中化合物的析出主要与降熔组元的扩散有关,中间层中B元素作为降熔组元,其含量的多少直接影响着接头化合物的形成数量;而Si元素由于在母材中的固溶度较高,其化合物在焊接过程中不易析出.

GH99 alloys were joined by transient liquid phase(TLP) process using self-designed Ni-Cr-Si-B interlayers.The effects of joining parameters and interlayer components on the interfacial microstructure of the joints were investigated with SEM and EDS.The results showed that with the increase of holding time and temperature,the precipitation of the compounds reduced and the microstructure of the joints became more uniform.The precipitation of the compounds in the joints was related to the diffusion of the melting point depressants.B element in the interlayer was one of the melting point depressants,and its content directly affected the quantity of the compounds in the joints.Because Si element in the base alloy was highly solid dissolved,the Si-rich compounds were reluctant to precipitate during bonding.