S_3iN_4/Ni/TiAl扩散连接接头界面结构及性能  

Interfacial microstructure and properties of Si_3N_4/Ni/TiAl joint boned by diffusion-bonding

作　　者：曹健[1] 宋晓国[1,2] 王义峰[1] 冯吉才[1] 

机构地区：[1]哈尔滨工业大学现代焊接生产技术国家重点实验室,哈尔滨150001 [2]黑龙江工程学院材料与化学工程系,哈尔滨150050

出　　处：《焊接学报》2011年第6期1-4,113,共4页Transactions of The China Welding Institution

基　　金：黑龙江省杰出青年基金资助项目(2004793);国家自然科学基金资助项目(50805038)

摘　　要：采用厚度为80μm的镍中间层实现了Si3N4陶瓷和TiAl合金的扩散连接.采用扫描电镜(SEM),能谱检测(EDS)等分析方法确定了TiAl/Ni/Si3N4扩散焊接头的典型界面结构为TiAl/Al5Ni2Ti3/AlNi2Ti/Ni3(Ti,Al)/Ni(s,s)+Ni3Si/Si3N4.重点分析了连接温度对接头界面结构及力学性能的影响规律.结果表明,随着温度的升高,TiAl/Ni界面处元素互扩散速率逐渐加快,导致各化合物层厚度增加.同时,Si3N4与镍的反应加快致使在Si3N4/Ni界面处出现孔洞;连接温度过高时,易在该孔洞区产生裂纹.当连接温度1 000℃,保温时间2 h时接头抗剪强度达到最大为104.2 MPa.压剪过程中,裂纹起裂于SiN/Ni界面处,随后向SiN侧扩展并最终断裂于陶瓷母材.Diffusion bonding of Si3N4 ceramic and TiAl alloy was achieved using 80μm thick Ni foil as interlayer.The interfacial microstructure was TiAl/Al5Ni2Ti3/AlNi2Ti/Ni3(Ti,Al)/Ni(s,s)+Ni3Si/Si3N4,which was analyzed by SEM,EDS and XRD.The effect of bonding temperature on interfacial microstructure and joining properties of the Si3N4/Ni/TiAl joints were investigated in details.With an increase of temperature,the inter-diffusion rate of alloying elements at the TiAl/Ni and Ni/Si3N4 interfaces increased gradually,which led to an increase in thickness of reaction layers.A porous zone formed between Ni and Si3N4 when the temperature was relatively high,where cracks performed to come forth.The highest shear strength of 104.2 MPa was obtained when the specimen was bonded at 1 000 ℃ for 2 h.Fracture analysis indicated that cracks initiated at the Si3N4/Ni interface and propagated to Si3N4 substrate finally ruptured within ceramic.

关 键 词：Si3 N4陶瓷 TIAL合金 扩散连接 界面组织 

分 类 号：TG115.28[金属学及工艺—物理冶金]