钛合金刚性拘束热自压连接及接头组织与力学性能

Microstructure and mechanical properties of the titanium alloy joints by rigid restraint thermal self-compressing bonding

摘要:

提出了一种新的固相连接方法—刚性拘束热自压连接技术，基本原理是：在无外力作用的条件下，利用集中热源非熔化局部加热刚性拘束的待连接材料，形成热弹塑性应力应变场，对连接处热塑性状态金属产生自挤压，实现扩散和固相连接。实验中，在真空条件下，利用电子束热源对TC4进行了刚性拘束热自压连接，验证了刚性拘束热自压连接的可行性，并分析了连接温度对刚性拘束热自压连接的影响。结果表明：热自压连接方法原理可行，加热温度显著影响钛合金接头的组织和性能，在TC4合金相变点以下温度加热时，接头组织均匀，综合力学性能优异。

Abstract:

AA new solid state joining method named as rigid restraint thermal self-compressing bonding is proposed. Solid joints can be produced using localized heating method without the use of external force. The butted surfaces of the rigid restrained plates is locally heated to produce a thermal elastic-plastic stress-strain field to compress the zones to be bonded, and in its turn to facilitate the diffusion of interface atoms to form solid joint. Experiments were conducted on TC4 titanium plates to show the feasibility of rigid restraint thermal self-compressing bonding using electron beam as heat source. Thermal cycles of rigid restraint thermal self-compressing bonding were measured. Microstructure and mechanical properties of bonded joint were investigated. Moreover, effects of temperature on rigid restraint thermal self-compressing bonding were analyzed. Results show that perfect solid state joint can be performed. The effects of thermal cycles and the peak temperature on microstructure and mechanical properties of bonded joint are notable. Peak temperature lower than the β transus temperature of TC4 alloy is recommended to perform homogeneous microstructure of the solid state bonded joint with high mechanical properties equal to base metal.