CAJ | 학술논문

通过热力学计算可知,在CaH_2-TiO_2-Al体系中用还原扩散法制备TiAl合金是可能的.该反应为一级反应,采用液-固未反应核模型探讨其反应机制.结果表明,TiO_2还原成纯金属Ti非常迅速,不是反应的控制步骤,界面化学反应为反应的控制环节.反应的表观活化能为76.84 kJ·mol~(-1).当CaH_2的量为理论计算量的1.5倍时反应充分;Al粉的粒度对反应没有影响;反应温度为1423 K、反应时间为8 h时,TiAl合金的转化率接近100%.
통과열역학계산가지,재CaH_2-TiO_2-Al체계중용환원확산법제비TiAl합금시가능적.해반응위일급반응,채용액-고미반응핵모형탐토기반응궤제.결과표명,TiO_2환원성순금속Ti비상신속,불시반응적공제보취,계면화학반응위반응적공제배절.반응적표관활화능위76.84 kJ·mol~(-1).당CaH_2적량위이론계산량적1.5배시반응충분;Al분적립도대반응몰유영향;반응온도위1423 K、반응시간위8 h시,TiAl합금적전화솔접근100%.
It is possible on thermodynamics to prepare TiAl alloy in CaH_2-TiO_2-Al system by Reduction-Diffusion method. It is a first-class reaction, whose mechanism was discussed by liquid-solid contracting core model. Results show that TiO_2 is reduced to Ti rapidly, which is not the rate-controlling step of the reaction. The interfacial chemical reaction is the rate-controlling step of the reaction. The apparent activation energy of the reduction-diffusion reaction is 76.84 kJ/mol. There is sufficient reaction when the entering quantity of CaH_2 is 1.5 times of theoretic quantity. Al powder granularity doesn't influence the reaction. The transformation efficiency of TiAl alloy is about 100% when the reaction temperature is 1423 K and the reaction time is 8 h.