TC4钛合金高温氧化行为

研究了TC4钛合金在650、750、850℃的循环氧化和25~1000℃范围内的连续变温氧化的氧化行为。采用电子天平或综合热分析仪、XRD、SEM和EDS分析了合金的氧化动力学、氧化膜的物相、表面形貌、截面结构及元素分析。结果表明:650℃循环氧化和连续变温氧化动力学曲线符合抛物线规律、750℃循环氧化符合抛物线-直线混合规律、850℃循环氧化符合直线规律。氧化膜由薄而致密的Al_2O_3外层和厚而疏松的TiO_2内层组成。随氧化温度升高,氧化膜厚度增加,但出现裂纹或剥落。

High Temperature Oxidation Behavior of TC4 Alloy

The cyclic oxidation and continuous variable temperature oxidation behavior of the TC4 alloy have been investigated. The oxidation kinetics, phase, surface morphologies, cross-sectional morphologies and element distribution of the oxide scales after oxidation were studied by electronic microbalance or comprehensive thermal analyzer instrument, X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results indicate that cyclic oxidation of TC4 alloy agrees with the parabolic law at 650 °C and the same goes with the continuous variable temperature oxidation, and the cyclic oxidation follows the parabolic-linear law at 750 °C, which obeys the linear law at 850 °C. The double oxide scales formed on the surface of the TC4 alloy is composed by two layers: the Al2O3 outer layer which is thin and dense as well as the TiO2 inner layer which is thick and loose. The thickness of oxide scales is growing with the increasing oxidation temperature, while the cracks and the spallation occur.