Ti2AlNb基合金高温氧化初期热力学分析  

Thermodynamic analysis of Ti2AlNb-based alloy in the initial stage of high temperature oxidation

作　　者：杨家俊 刘立斌[1] 赵云 章立钢[1] YANG Jiajun;LIU Libin;ZHAO Yun;ZHANG Ligang(School of Material Science and Engineering,Central South University,Changsha 410083,China)

机构地区：[1]中南大学材料科学与工程学院,长沙410083

出　　处：《粉末冶金材料科学与工程》2020年第2期98-103,共6页Materials Science and Engineering of Powder Metallurgy

基　　金：科技部重大专项(2016YFB0701301)。

摘　　要：运用相图计算技术,研究Ti-22Al-xNb(x=0~30%,摩尔分数)合金在1 000℃氧化的初始氧化产物,并预测Ti-22Al-27Nb和Ti-22Al-15Nb合金在此温度下氧化初期的各相质量分数及相组成的变化。结果表明:随氧分压增大,基体中的Bcc_B2相向Hcp_A3相转变以溶解增加的O(氧)。合金中元素的氧化顺序为Al,Ti,Nb。Al2O3,Halite(TiO)和NbO分别在氧分压为4.72×10^-32,4.11×10^-30和5.53×10^-25 MPa时出现。随氧分压增大,Ti与Nb的氧化产物均往含氧量更高的方向发展。与Ti-22Al-27Nb相比,Ti-22Al-15Nb合金中NbO和NbO2的质量分数明显减小,而Al2O3的质量分数显著增加。The initial oxidation products of Ti-22Al-xNb(x=0?30%,mole fraction)alloy at 1000℃were calculated by phase diagram calculation.The changes of mass fraction and phase composition of Ti-22Al-27Nb and Ti-22Al-15Nb alloys at the initial stage of oxidation at this temperature were predicted.The results show that,with the increase of oxygen partial pressure,Bcc_B2 phase in the matrix changes to Hcp_A3 phase to dissolve the increased O(oxygen).The oxidation order of the elements in the alloy is Al,Ti,Nb.Al2O3,Halite(TiO)and NbO appear at the oxygen partial pressures of 4.72×10^?32 MPa,4.11×10^?30 MPa and 5.53×10^?25 MPa,respectively.With the increase of oxygen partial pressure,the oxidation products of Ti and Nb tend to higher oxygen content.Compared with Ti-22Al-27Nb,the mass fractions of NbO and NbO2 in Ti-22Al-15Nb alloy decrease obviously,while the mass fraction of Al2O3 increases obviously.

关 键 词：TI2ALNB 相图计算 高温氧化 相组成 热力学计算 

分 类 号：TG146.23[一般工业技术—材料科学与工程]