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采用粉末热等静压+等温锻造复合工艺制备出细晶Ti-17粉末合金材料,并研究了粉末合金在不同条件下的超塑性变形特性。结果表明:粉末热等静压+等温锻造复合工艺可制备出细晶Ti-17粉末钛合金,合金退火后组织内部等轴α相细小。在780~920℃以及应变速率5×10~(-4)~1×10~(-2)s~(-1)内粉末合金都具有超塑性。粉末合金超塑性变形是以晶界滑动为主,以扩散蠕变和晶内位错滑移为辅。孔洞的形核、长大和连接是导致粉末合金超塑性变形失效的主要原因。
The fine grained Ti-17 powder alloy was prepared by powder hot isostatic pressing + isothermal forging composite process, and the superplastic deformation properties of the powder alloy under different conditions were studied. The results show that the fine isothermal Ti-17 powder titanium alloy can be prepared by powder hot isostatic pressing and isothermal forging composite process. The isothermal α phase of the alloy is fine after annealing. In the range of 780-920 ℃ and the strain rates of 5 × 10 -4 ~ 1 × 10 -2 s -1, the powder alloys all have superplasticity. Superplastic deformation of the powder alloy is based on the grain boundary sliding, with diffusion creep and intracrystalline dislocation slip as a supplement. The nucleation, growth and connection of the holes are the main reasons leading to the failure of the superplastic deformation of the powder alloy.