Effect of hydrogen concentration on various properties of gamma TiAl

• 作 者: JiWeiWang;H.R.Gong;
• 机 构: State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083, China
• 出 处: 第十三届国际凝聚态理论与计算材料学会议(The 13th International Conference on Con
• 发表日期: 2014年期

　　During the past decades, the interaction between hydrogen (H) and gamma TiAl phase has induced considerable interests among researchers [1-5].The present study is dedicated to have a systematic investigation of structural, mechanical, and thermodynamic properties of gamma TiAl phases as a function of H composition.First principles calculation reveals that the TiAlH phases become relatively less stable after the addition of more H atoms, and that the H migration from tetrahedral interstitial site to octahedral site in gamma TiAl should be much easier than that between octahedral sites.Calculation also shows that H concentration has an important effect on mechanical properties of TiAlH phases, and that the energetically favorable TiAlH phase should possess bigger E, G, and G/B values as well as lower elastic anisotropy.Moreover, it is found that the heat capacities of TiAlH phases increase with the increase of H concentration, and that the coefficients of thermal expansion of TiAl and TiAlH phases decrease with the increase of pressure.