TC4/TNM钎焊接头界面组织及力学性能

Interfacial Microstructure and Mechanical Property of TC4/TNM Brazed Joint

采用Ti-25.65Zr-13.3Cu-12.35Ni-3Co-2Mo(质量分数,%)非晶箔带钎料在900~1020℃/10 min工艺下真空钎焊连接TC4和TNM合金,并系统研究了TC4/TNM钎焊接头的界面组织和形成机制以及钎焊温度对界面组织和剪切强度的影响规律。结果表明:钎焊温度900~980℃时接头的组织为TC4/细小网篮状(α+β)-Ti/γ-(Ti,Zr)2(Cu,Ni)+α-Ti/Ti_(3)Al/TNM,随钎焊温度的升高,钎缝中硬脆的γ相减少、韧性的α-Ti增加。钎焊温度为1000和1020℃时,接头的界面反应层由3层演变成2层且对应的物相分别是韧性差的粗针状(α+β)-Ti和Ti_(3)Al,粗针状(α+β)-Ti随温度的升高进一步粗化。钎焊接头抗剪切强度随温度的升高先增大后减小,钎焊温度980℃时抗剪切强度达到最大值494.83 MPa。剪切测试的钎焊接头均脆性断裂于TNM侧的钎缝中。

Vacuum dissimilar brazing of TC4 alloy and TNM alloy was performed at 900-1020°C for 10 min using amorphous Ti-25.65Zr-13.3Cu-12.35Ni-3Co-2Mo(wt%)filler.The interfacial microstructure and formation mechanism of the TC4/TNM brazed joint were studied.The variation of the interfacial microstructure and shear strength of the brazed joints with brazing temperature were investigated.The results show that the interfacial microstructure of the TC4/TNM joints brazed at 900-980°C are TC4/fine basket weave(α+β)-Ti/γ-(Ti,Zr)2(Cu,Ni)+α-Ti/Ti_(3)Al/TNM.The amount of brittleγ-(Ti,Zr)2(Cu,Ni)decreases but that of the ductileα-Ti increases with the brazing temperature increasing.Once the brazing temperature increases to 1000°C and to 1020°C,the interfacial reaction layer of the TC4/TNM brazed joints transforms from three layers into two layers,which consist of coarse acicular(α+β)-Ti with poor ductility and Ti_(3)Al.And the coarse acicular(α+β)-Ti is further coarsened with the brazing temperature increasing.The shear strength of the TC4/TNM brazed joint increases first and then decreases with the increase in brazing temperature.The maximum shear strength of 494.83 MPa is obtained at 980°C.The brittle fracture primarily occurs in the brazing seam near TNM side regardless of brazing temperature during shear test.