【摘要】 用最小二乘法对渗硅TiAl基合金在900、1000、1100和1200℃的循环氧化数据进行了拟合。结果表明:渗硅TiAl基合金900℃氧化在所测试的118h内氧化动力学曲线呈抛物线规律;1000℃氧化在0～50h之间呈抛物线型规律,50～118h之间呈直线型氧化规律;1100℃氧化在0～4h之间呈抛物线型规律,4～8h之间呈直线型氧化规律,8～16h呈二次型加速氧化规律,16h出现剥落现象;1200℃循环氧化在0～4h呈二次型加速氧化规律,4h后出现剥落现象。相应的氧化速率常数为:900℃时Kp≈4·924×10-5mg2cm-4h-1,1000℃时Kp≈7·778×10-5mg2cm-4h-1,1100℃时Kp≈9·392×10-2mg2cm-4h-1。并对渗硅层在温度超过1000℃后的氧化机制进行了初步探讨。更多还原

【Abstract】 The cyclic oxidation resistance of pack siliconized TiAl-based alloy was tested at 900 ℃,1000 ℃,1100 ℃ and 1200 ℃.The results show that three kinds of oxidation kinetics behavior,parabolic,linear and quadratic,are revealed by analyzing the experimental data with least square method.At 900 ℃,only parabolic oxidation behavior appeares during the whole cyclic oxidation test of 118 h.At 1000 ℃,the oxidation behavior is parabolic at the initial stage up to 50 h,and becomes linear from 50 h to 118 h.At 1100 ℃,the oxidation behavior is parabolic at the initial stage up to 4 h,and becomes linear from 4 h to 8 h,and then becomes quadratic from 8 to 16 h,and spallation occurs at the time of 16 h.At 1200 ℃,only quadratic oxidation behavior appears during the whole cyclic oxidation test period of 4 h,and spallation occurs.The corresponding oxidation constants obtained by fitting the curves are:Kp≈4.924×10-5 mg2cm-4h-1 at 900 ℃,Kp≈7.778×10-5 mg2cm-4h-1 at 1000 ℃,Kp≈9.392×10-2 mg2cm-4h-1 at 1100 ℃.The oxidation mechanism of the temepature above 1000 ℃ was discussed.更多还原