ZTA复相陶瓷/GH3536镍基合金钎焊接头组织演变和力学性能

Microstructural Evolution and Mechanical Properties of ZTA Composite Ceramic/GH3536 Nickel-Based Alloy Brazed Joints

摘要:

本研究使用AgCuAlTi钎料实现了氧化锆增韧氧化铝（zirconia toughened alumina，ZTA）复相陶瓷与GH3536镍基合金的钎焊连接，探究了钎焊温度和保温时间对接头界面组织和抗剪强度的影响。在980 ℃保温10 min的钎焊条件下，接头的典型界面结构为ZTA/TiO+Ti₃(Cu,Al,Ni)₃O/Ag(s,s)+Cu(s,s)/AlNi₂Ti+Ti₂Ni/Fe-Cr+Ni-Fe-Cr/GH3536。陶瓷基体中的Al₂O₃和ZrO₂两组分共同参与界面反应，Al₂O₃与液态钎料中的Ti和Cu反应生成Ti₃Cu₃O，ZrO₂与Ti和Cu反应生成TiO和Ti₃Cu₃O，Al与Ni固溶进入Ti₃Cu₃O形成Ti₃(Cu,Al,Ni)₃O。随着钎焊温度上升（940~980 ℃）和保温时间的延长（1~10 min），TiO、 Ti₃(Cu,Al,Ni)₃O和AlNi₂Ti厚度增加，在980 ℃下保温10 min获得具有最大抗剪强度（123 MPa）的接头。当钎焊温度超过980 ℃或保温时间超过10 min时，陶瓷侧的TiO转化为Ti₃(Cu,Al,Ni)₃O，同时生成大量的AlNi₂Ti，过度消耗钎料中的Ti，阻碍了Ti₃(Cu,Al,Ni)₃O的生成，使得Ti₃(Cu,Al,Ni)₃O层不再连续，最终导致接头抗剪强度下降。

Abstract:

Reliable zirconia-toughened alumina (ZTA) composite ceramic/GH3536 nickel-based alloy brazing joints were fabricated using AgCuAlTi filler. The effects of brazing temperature and holding time on the interfacial microstructure and shear strength of the brazing joints were investigated. The typical interfacial structure of the joint brazed at 980 ℃ for 10 min is ZTA/TiO+Ti₃(Cu,Al,Ni)₃O/Ag(s,s)+Cu(s,s)/AlNi₂Ti+Ti₂Ni/Fe-Cr+Ni-Fe-Cr/GH3536. The two components of Al₂O₃ and ZrO₂ in the ceramic matrix participate in the interfacial reactions together. Ti₃Cu₃O is formed by Al₂O₃ with Ti and Cu in the liquid filler and ZrO₂ reacts with Ti and Cu to form TiO and Ti₃Cu₃O. Ti₃(Cu,Al,Ni)₃O is formed through the solid-solution of Al and Ni into Ti₃Cu₃O. With the increase in brazing temperature (940–980 ℃) and holding time (1–10 min), TiO, Ti₃(Cu,Al,Ni)₃O and AlNi₂Ti layers are thickened, and the joint brazed at 980 ℃ for 10 min has the maximum shear strength of 123 MPa. When the brazing temperature exceeds 980 ℃ or holding time is longer than 10 min, TiO on the ceramic side is converted to Ti₃(Cu,Al,Ni)₃O. Meanwhile, a large amount of generated AlNi₂Ti excessively consumes Ti in the filler, thereby hindering the generation of Ti₃(Cu,Al,Ni)₃O. So the Ti₃(Cu,Al,Ni)₃O layer is no longer continuous, which ultimately degrades the shear strength of the joint.