低成本高性能粉末冶金钛合金

The preparation of high-performance titanium alloys by powder metallurgy

摘要:

粉末冶金是短流程制备低成本、高性能钛及钛合金的有效方法。低成本氢化脱氢（HDH）钛粉可用于制备粉末冶金钛合金制件，但由于受间隙原子含量高、烧结致密度低和微观组织粗大等因素影响，使粉末冶金钛制品的组织性能优势得不到发挥。实验采用氢化脱氢钛粉—冷等静压—真空烧结的技术路线制备了Ti-6Al-4V烧结坯，间隙原子含量低（O<0.16 wt.%, N<0.05 wt.%, H<0.015 wt.%），具有均匀细小的近等轴?组织，良好的室温拉伸性能（UTS>930 MPa, YS>870 MPa, El>14%）。实验同时表明了HDH工艺制备低间隙原子含量钛粉的可行性，间隙原子含量的增加主要源于粉末及压坯的操作、转移和储存过程。得益于粉末冶金钛合金的细晶和近终成形特点，它无需通过开坯锻造，并且近成型的烧结坯能够提高材料利用率，减少后续热加工变形量及加工道次。因此，以粉末钛合金烧结坯替代锻坯进行后续的塑性加工能够大幅度降低钛合金构件及型材的成本。

Abstract:

Powder metallurgy is an effective way to produce low-cost and high-performance titanium and titanium alloys. The as-sintered Ti-6Al-4V ingots produced by hydrogenated dehydrogenation, cold isostatic pressing and vacuum pressure-less sintering have low interstitials content (O<0.16 wt.%, N<0.05 wt.%, H<0.015 wt.%), near-equiaxed ? microstructure, better mechanical properties (UTS>930 MPa, YS>870 MPa, El>14%). The results also show that HDH process can obtain very low interstitials content titanium powder. The increase of interstitials concentration is mainly due to the operation, transfer and storage of powder and powder compact. Benefit from fine grain and near-net-shape characteristics of powder metallurgy titanium alloy, as-sintered ingots can be directly used to prepare final titanium alloy products without cogging down. Then, the near shape PM Ti can increase materials utilization rate, reduce deformation during hot working. So, the as-sintered PM Ti instead of as-forged Ti can significantly reduce the cost of titanium products.