多级深度还原法制备Ti6Al4V合金粉体的基础研究

Basic Research on Preparation of Ti6Al4V Alloy Powder by Multistage depth reduction process

摘要:

目前Ti6Al4V合金粉体的生产方法主要有雾化法、机械合金法和氢化脱氢法,它们都以Kroll法生产海绵钛为基础。使用钛的氧化物作为原料的熔盐电解法和金属热还原法仍处于研究阶段。本文依据变价金属Ti和V的氧化物在还原过程中逐级还原的特性,提出使用金属氧化物(TiO₂, V₂O₅)作为原料的多级深度还原法制备Ti6Al4V合金粉体的新思路。首先计算了TiO₂-V₂O₅-Mg-Ca体系的吉布斯自由能变,结果表明先进行镁热自蔓延反应,后进行钙热深度还原反应制备Ti6Al4V合金粉体在热力学上具备可行性。然后通过实验进行了的验证。镁热自蔓延反应产物酸浸后除去MgO可得到氧含量为15.84%的多孔Ti-Al-V-O前驱体。配入金属Ca后进行深度脱氧可得到低氧Ti6Al4V合金粉体(Al: 6.2wt.%, V: 3.64wt.%, O: 0.24wt.%, Mg: 0.01wt.%, Ca: < 0.01wt.%)。

Abstract:

_{:At present, the production methods of Ti6Al4V alloy powder mainly include atomization method, mechanical alloy method, and hydrodehydrogenation method, but they are still based on the Kroll method to produce sponge titanium. Molten salt electrolytic method and metal reduction method are still in the laboratory research stage. According to the thermodynamic characteristics of step-by-step reduction of high valent metal oxides and the thermodynamic transmutation of different equilibrium phases in the reduction process, a new idea of preparing Ti6Al4V alloy powder by multi-stage reduction of metal oxides (TiO2, V2O5) as raw materials were put forward. Firstly, the Gibbs free energy change of TiO2-V2O5-Mg-Ca system is calculated. The results show that it is thermodynamically feasible to obtain Ti6Al4V alloy powder by magnesium thermal self propagating reaction and calcium thermal deep reduction reaction. Then it is verified byexperiments. After acid leaching of the product of magnesium thermal self-propagating reaction, MgO can be removed to obtain a porous Ti-Al-V-O precursor with an oxygen content of 15.84wt.%.Low-oxygen Ti6Al4V alloy powder(Al: 6.2wt.%, V: 3.64wt.%, O: 0.24wt.%, Mg: 0.01wt.%, Ca: < 0.01wt.%) can be obtained by adding metal Ca in the later stage for deep deoxidation。}