Ti2AlNb合金与钛基复合材料的低温固相扩散连接机理

Ti2AlNb合金和Ti基复合材料可以使用直接固相扩散的方法进行连接,但较高的扩散温度使得母材发生相变,其接头性能也因此变差。采用Ti箔中间层的方法优化Ti2AlNb合金和Ti基复合材料的固相扩散连接接头性能。结果表明:加入30μm的Ti箔中间层后,扩散连接温度由950℃降低至850℃,变形率由5%降低至1.7%,扩散连接温度的降低有效地改变了接头界面的组织,典型界面组织为Ti2AlNb/富B2相/α+β双相组织/Ti基复合材料,其中接头界面处α+β双相组织的形成提高了接头的强度。最佳扩散连接工艺参数为850℃/60min/5 MPa时,剪切强度达到最大值399MPa,实现了Ti2AlNb和Ti基复合材料在低温下的扩散连接。

Solid phase diffusion bonding of Ti2 AlNb alloy and titanium matrix composites at low temperature

The Ti2AlNb alloy and the titanium matrix composites can be joined by direct solid phase diffusion, but the high diffusion temperature causes the base metal to undergo a phase transition, even the joint properties were therefore deteriorated. A method for optimizing the properties of solid phase diffusion joints of Ti2AlNb alloy and Ti matrix composites was proposed by using Ti foil intermediate layer. The results show that after adding 30 μm Ti foil intermediate layer, the diffusion bonding temperature reduces from 950 ℃ to 850 ℃, the deformation rate reduces from 5% to 1.7%, and the decreasing of diffusion bonding temperature can effectively change the structure of the joint interface. The typical interface is Ti2AlNb/B2 phase/α+β dual phase structure/Ti matrix composite, in which the strength of the joint increases by the formation of α+β dual phase structure at the joint interface.When the optimum diffusion bonding parameter is 850 ℃/60 min/5 MPa, the shear strength reaches a maximum value of 399 MPa. The diffusion bonding of Ti2AlNb and Ti based composite at low temperature is realized.