以铜和Cu-Ti作为中间层的TiAl/GH3536扩散焊

采用铜箔和Cu-Ti合金作为中间层进行了TiAl和GH3536的扩散焊试验.以铜箔作为中间层在935℃/10 MPa/1 h参数下获得的焊缝组织以Ti（Cu,Al）2,AlCu2Ti和AlNi2Ti相为主,焊缝中存在裂纹.接头室温平均抗剪强度仅有31 MPa.以Cu-Ti合金作为中间层在935℃下采用三种不同参数进行了TiAl和GH3536的液相扩散焊试验.当加压3 MPa,保温10 min时,扩散焊缝中央还存在着宽度约5μm的残留相.保温时间延长至1 h,焊缝形成了较为均匀的分层组织,获得的接头室温抗剪强度最高,达180 MPa.增大压力至20 MPa,保温2 h获得的接头中出现AlNi2Ti相,接头平均室温抗剪强度下降至90 MPa.

Diffusion bonding of TiAl and GH3536 superalloy with Cu and Cu-Ti as interlayers

TiAl alloy was joined to GH3536 superalloy with diffusion bonding method using Cu foil and Cu-Ti alloy as the interlayers.The microstructure and property of the joints bonded at different conditions were tested.The results showed that the joint bonded at the condition of 935 ℃/10 MPa/1 h with Cu foil interlayer,was mainly composed of Ti(Cu,Al)2,AlCu2Ti and AlNi2Ti phases.However,some microcracks appeared throughout the joint and the corresponding average shear strength at room temperature was only 31 MPa.Liquid-phase diffusion bonding between TiAl and GH3536 was investigated by using Cu-Ti interlayer at 935 ℃.Under the bonding condition of 3 MPa and 10 min,residual phases of the Cu-Ti interlayer were visible in the central part of the joint,with the thickness of about 5 μm.Prolonging the holding time to 1h,several homogeneous layers appeared in the joint,and it exhibited the maximum shear strength of 180 MPa.AlNi2Ti phase was formed in the joint bonded at an increasing pressure of 20 MPa and with the holding time of two hours,while its average shear strength decreased to 90 MPa.