SiC/TiAl扩散连接接头的界面结构及连接强度

Interface Structures and Bonding Strength of SiC/TiAl Joints in Diffusion Bonding

对常压烧结的 Ｓｉ Ｃ 陶瓷与 Ｔｉ Ａｌ 金属间化合 物进行了真空扩散连接。采用扫描电镜、电子探针和 Ｘ 射线衍射分析等手段确定了反应产物的种类和接头的界面结构，并用拉剪试验评价了接 头的连接强度。研究结果表明， Ｓｉ Ｃ 与 Ｔｉ Ａｌ 扩散连接中生 成了 Ｔｉ Ａｌ２ 、 Ｔｉ Ｃ 和 Ｔｉ５ Ｓｉ３ Ｃｘ 三种新相，接头的界 面结构为 Ｓｉ Ｃ／ Ｔｉ Ｃ／（ Ｔｉ Ｃ＋ Ｔｉ５ Ｓｉ３ Ｃｘ）／（ Ｔｉ Ａｌ２ ＋ Ｔｉ Ａｌ）／ Ｔｉ Ａｌ 。在１５７３ Ｋ 和１ ．８ ｋｓ 的连接条件下，接头室温剪切强度达到２４０ Ｍ Ｐａ ，高温（９７３ Ｋ） 剪切强度达到２３０ Ｍ Ｐａ 。

Diffusion bonding of Pressureless-sintered SiC ceramic to TiAl intermetallic compound was carried out. The kinds of the reaction products and the interface structures of the joints were investigated by SEM, EPMA and XRD. The bonding strength of the joints was evaluated by tension-shear test. The experimental results showed that the three kinds of new phases,TiAl 2, TiC and Ti 5Si 3Cx, occur during the diffusion bonding of SiC to TiAl and that the interface structures of the joints can be expressed by SiC/TiC/(TiC+Ti 5Si 3C X)/(TiAl 2+TiAl)/TiAl. The shear strength of the joint, which was bonded at 1573 K for 1.8 ks, is up to 240 MPa at room temperature and 230 MPa at the test temperature of 973 K.