加热时间对钛合金热自压连接及接头组织性能影响

Effect of heating time on rigid restraint thermal self-compressing bonding of TC4 alloy

摘要:

对不同加热时间下获得的钛合金刚性拘束热自压连接接头进行了连接界面光学显微镜观察，背散射电子衍射组织分析和接头拉伸力学性能测试，分析了加热时间对连接接头界面缺陷、组织和力学性能的影响。同时，利用热弹塑性有限元模型分析了连接中热应力应变演变过程，阐明了加热时间对连接接头界面焊合质量、组织和力学性能影响的原因。结果表明：加热峰值温度相当的情况下，加热时间增加，界面金属高温存在时间和受压应力作用时间以及横向压缩塑性变形增加，促进界面两侧原子扩散，界面未焊合缺陷减少，接头综合力学性能提高。加热时间至300s以上时，可以获得界面焊合质量好，组织均匀，综合力学性能优异的固相连接接头。

Abstract:

TC4 alloy was bonded by a new solid-state bonding process named as rigid restraint thermal self-compressing bonding at different heating time. Effect of heating time on bond interface, microstructure and mechanical properties was investigated through the optical microscope observation, scanning electron microscope analysis and mechanical properties test to the joints produced at different heating time. In the meantime, thermal stress-strain history during bonding was analyzed by finite element analysis. Results show that with the increase of heating time, the dwell time over high temperature, the action time of compressive stress and the transversal compressive plastic strain are increased which promote the atom diffusion between butt-specimens and thus the number of voids retained at bond interface is decreased. When the heating time is improved to more than 300s, sound solid-state joint with good bond interface, homogeneous microstructure and good mechanical properties is obtained.