TiAl基合金与40Cr钢扩散连接的界面结构及接合强度

用真空扩散连接的方法对Ｔｉａｉ／４０Ｃｒ钢进行了扩散连接。结果表明，在ＴｉＡＩ／４０Ｃｒ钢接头的界面处中出现了三个扩散层，它们分别是：邻接ＴｉＡＩ侧的ＴｉＡＩ＋ＦｅＡＩ＋ＦｅＡＩ２金属间化合物混合层，中间的ＴｉＣ层，靠近４０Ｃｒ钢侧的脱碳固溶层；并且随着焊接温度的提高，保温时间的延长，三个扩散层的厚度均显著增大。力学性能测试表明，ＴｉＡＩ／４０Ｃｒ扩散连接接头的拉伸强度很低，断口为脆性断裂，主要断裂在界面层中的ＴｉＣ处。为了获得结合较好拉的伸强度较高的ＴｉＡＩ／４０Ｃｒ钢扩散连接接头，宜采用高温短时规范，以达到控制及减少脆性相及金属间化合物的目的。

INTERFACE STRUCTURE AND BOND STRENGTH OF DIFFUSIONG -BONDED JOINT OF TiAl-BASE ALLOY TO 40Ct STEEL

TiA1 alloy was diffusion bonded to 40Cr steel in vacuum furnace. Results showed, at the TiA1 -40Cr inter face, the reaction layer of mixture was formed closest to TiA1 base, TiC layer was formed in the middle and obvious decarbonised layer was formed closest to 40Cr steel side. The widths of the three reaction layer increased with the increase of the bond temperature and the bond time. The ambient ultimate tensile strengths of the tested joints were poor, and fractography revealed that all joints fractured in the TiC layer, producing brittle cleavage fracture surface. High bond temperature and short bong time was propitious to decresing metallic compounds resulting in brittleness of the weld joint and obtaining high good properties of bonding.