Microstructure and mechanical properties of Al2O3/TiAl joints brazed with B powders reinforced Ag-Cu-Ti based composite fillers
Microstructure and mechanical properties of Al2O3/TiAl joints brazed with B powders reinforced Ag-Cu-Ti based composite fillers
复制标题
B粉增强Ag-Cu-Ti基复合填料钎焊Al2O3/TiAl接头的显微组织与力学性能
DOI：
10.1016/j.ceramint.2016.09.178
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发表时间：
2017-01-01
影响因子：
5.2
通讯作者：
Wang, Y.
中科院分区：
文献类型：
--
作者：
Niu, G. B.;Wang, D. P.;Wang, Y.
在本手稿中，Al2O3 陶瓷和 TiAl 合金与含有 B 粉末添加剂的 Ag-Cu-Ti 基复合填料进行钎焊。研究了B含量、Ti含量和钎焊温度对钎焊接头显微组织和力学性能的影响。钎焊接头典型界面组织为：Al2O3/Ti-3(Cu,Al)(3)O/Ag(s.s)+TiB+Ti(Cu,Al)+细A)Cu2Ti/块状AlCu2Ti+AlCuTi/TiAl。通过 B 添加剂与 Ti 反应原位合成 TiB 晶须，作为形成细 Ti(Cu, Al) 和 AlCu2Ti 晶粒的成核位点，并改善了结合性能。随着B含量的增加，钎缝中形成了更多的细晶粒，并且与Al2O3陶瓷相邻的Ti-3(Cu,Al)(3)O反应层的厚度减小。钎焊参数也影响接头微观结构。随着钎焊温度的升高，Ti3(Cu,Al)(3)O层和AlCu2Ti层不断生长。此外，钎缝中分散细晶粒的形成很大程度上取决于复合填料中的初始Ti含量。随着初始Ti含量的增加，TiB强化区域变宽，而块状AlCu2Ti含量逐渐减少。添加B增强复合填料钎焊的Al2O3/TiAl接头的最大剪切强度为148 MPa，比不添加B钎焊的Al2O3/TiAl接头提高了246%。接头剪切强度由连接材料之间的热膨胀失配、Ti3(Cu,Al)(3)O层的厚度以及接头中存在的缺陷的综合影响决定。
In this manuscript, Al2O3 ceramic and TiAl alloy were brazed with Ag-Cu-Ti based composite fillers containing B powder additive. The effects of B content, Ti content, and the brazing temperature on the microstructure and mechanical properties of the brazed joints were investigated. The typical interfacial microstructure of the brazed joint was: Al2O3/Ti-3(Cu, Al)(3)O/Ag(s.s)+TiB+Ti(Cu, Al)+fine A)Cu2Ti/blocky AlCu2Ti+AlCuTi/TiAl. TiB whiskers synthesized in situ by the reaction of the B additive with Ti, served as nucleation sites for the formation of fine Ti(Cu, Al) and AlCu2Ti grains and improved the bonding properties. With increasing B content, more fine grains were formed in the brazing seam and the thickness of the Ti-3(Cu, Al)(3)O reaction layer adjacent to the Al2O3 ceramic decreased. Brazing parameters also influenced the joint microstructure. Growth of Ti3(Cu, Al)(3)O layer and AlCu2Ti formed with increase in brazing temperature. Moreover, the formation of dispersed fine grains in the brazing seam depended largely on the initial Ti content in the composite filler. With increase in initial Ti content, the TiB-reinforced area was broadened while the blocky AlCu2Ti content decreased gradually. The maximum shear strength of Al2O3/TiAl joint brazed with B-reinforced composite filler was 148 MPa, which was 246% higher than that brazed without B addition. The joint shear strength was determined by the combined influences of the thermal expansion mismatch between the joined materials, the thickness of the Ti3(Cu, Al)(3)O layer, and the presence of defects in the joints.