基于氢化脱氢钛粉制备低成本高性能钛合金

Preparation of Low-cost and High-performance Titanium Alloys Based on HDH Titanium Powder

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之一。采用氢化脱氢(HDH)制粉—冷等静压成形—真空烧结致密化的技术路线制备了间隙原子含量低(O <0. 16%、N <0. 05%、H <0. 015%,质量分数)、具有均匀细小近等轴α组织且室温拉伸性能(R_m为840～950 MPa、R_(P0. 2)为770～900 MPa、A为12%～16%)良好的Ti-6Al-4V合金烧结坯,证明了HDH工艺制备低间隙原子含量钛粉的可行性,而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。由于粉末冶金钛合金具有细晶和近净成形的特点,无需开坯锻造,并且近净成形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( PM) is an effective way to produce low-cost and high-performance titanium and titanium alloys. The as-sintered Ti-6Al-4V alloy ingots produced by hydrogenated dehydrogenation( HDH),cold isostatic pressing and vacuum pressure-less sintering have low interstitial atomic content( O < 0. 16 wt%,N < 0. 05 wt%,H < 0. 015 wt%),near-equiaxed α microstructure,better mechanical properties( R_m840 ～ 950 MPa,RP_(0.2)770 ～ 900 MPa,A12% ～ 16%). The results show that HDH process can obtain very low interstitial atomic content titanium powder. The increase of interstitial atomic 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 forging-cogging. Then,the near shape PM titanium can increase materials utilization rate,reduce deformation during hot working. So the as-sintered PM titanium instead of as-forged titanium can significantly reduce the cost of titanium products.