AgCuNiLi钎焊TiC金属陶瓷与GH3128界面结构及接头性能

Interfacial microstructure and properties of TiC cermet and GH3128 joint brazed using AgCuNiLi

摘要:

采用AgCuNiLi钎料对TiC金属陶瓷与GH3128镍基高温合金进行钎焊。研究结果表明：当钎焊温度为840℃,保温10min时,接头典型界面结构可以表示为：TiC金属陶瓷/(Cu,Ni)/Ag(s,s)+Cu(s,s)/(Cu,Ni)/GH3128。随着钎焊温度的升高或保温时间的延长,TiC金属陶瓷附近的(Cu,Ni)固溶体层厚度增大,且向钎料内部呈树枝状长大,钎料内部的Ag-Cu共晶组织逐渐减少。界面机理分析表明：钎料中Li的加入能促进界面上(Cu,Ni)固溶体的形成；但(Cu,Ni)固溶体的继续长大则受钎料中Cu元素的扩散程度控制。当加热温度由810℃升高到960℃,接头抗剪强度呈现先增大,然后缓慢减小的变化趋势。当加热温度为880℃、保温时间为10min时,接头抗剪强度达到最大值204MPa。

Abstract:

TiC cermet and GH3128 nickel-based superalloy was brazed using AgCuNiLi filler alloy. The results show that the interfacial microstructure of the joint brazed at 840°C for 10min is TiC cermet/(Cu,Ni)/Ag(s.s)+Cu(s.s)/(Cu,Ni)/GH3128. With the increase of temperature and holding time, the (Cu,Ni) solid solution at the TiC cermet side thickens and grows in the form of dendrite crystal; besides, the eutectic microstructure in the brazing alloy decreases. The analysis on the interfacial microstructure shows that the addition of Li in the alloy promotes the forming of the (Cu,Ni) solid solution. However, the continuing growth of the (Cu,Ni) solid solution is controlled by diffusion of the Cu element in the brazing alloy. Shear strength of the joint increases gradually and then decreases slowly with the increase of the brazing temperature. The highest shear strength of 204MPa was obtained when the specimens were brazed at 880°C for 10min.