Ti2AlNb合金超塑成形／扩散连接工艺研究

Research on superplastic forming/diffusion bonding technology of Ti2AlNb alloy

摘要:

为研究Ti₂AlNb合金的超塑性及其成形性能，在920~960℃温度区间，应变速率10^-3-10^-5s^-1范围内对该材料的超塑性进行了研究，结果表明该材料在960℃，1×10^-4s^-1应变速率时具有较好超塑性，最大延伸率可达230%，应变速率敏感性指数为0.31；用Marc软件模拟了Ti₂AlNb合金的3层结构超塑成形过程，对缺陷形成进行分析，分析表明在芯板厚度为面板厚度1/3时，可改善3层结构表面缺陷；用超塑成形/扩散连接工艺实现了Ti₂AlNb合金3层结构的制备，并通过改变芯板和外层面板的厚度比改善了3层结构表面缺陷，结果表明，采用合理的工艺方式及工艺参数能够实现该合金的空心夹层结构的制备.

Abstract:

In order to study the Ti₂AlNb alloy superplastic forming and its performance, the materials with temperature range in 920~960℃ and rate of strain 10^-3~10^-5 s^-1 within the scope of superplasticity are studied. The results show that the material at 960℃, 1×10^-4 s^-1 when the strain rate has a good superplasticity with maximum elongation rate reaching 230% and strain rate sensitivity index 0.31. Marc software was used to simulate the three layers structure of Ti₂AlNb alloy superplasticy forming process, and the formation of defects was analysed. The analysis results show that the 1/3 of the core sheet thickness of the face sheet thickness, can effectively improve the three layers structure of surface defects; Combined with superplastic forming/diffusion bonding process, it realizes Ti₂AlNb alloy the preparation of three layers structure, and improves three layers structure surface defects by changing the core sheet and the thickness of the face sheets. The results show that using reasonable technology and process parameters can achieve the preparation of hollow sandwich structure of the alloy.