高热负荷作用下钨的热疲劳损伤研究

Thermal Fatigue Damage of Tungsten Under High Heat Load

利用实验室自主搭建的电子束热疲劳测试系统,研究了再结晶态钨在功率为141.5 MW/m^2,不同循环次数下热疲劳损伤性能的变化规律。采用扫描电子显微镜(SEM)观测了损伤后表面形貌的变化,采用原子力显微镜(AFM)观测了损伤表面的三维形貌的变化,同时也测出损伤表面粗糙度。采用显微硬度计测试了热疲劳损伤后晶粒表面显微硬度的变化。结果表明:随循环次数的增加,钨热疲劳损伤加剧,当循环1000次时,钨表面已经有熔融的形貌出现;测得损伤表面的粗糙度随循环次数呈近似线性变化;损伤之后的显微硬度先升高后降低,主要是由于存在疲劳硬化的现象。

The thermal fatigue damage of recrystallization tungsten with different cycle times was studied at power of 141.5 MW/m^2 by electron beam thermal fatigue test system which was built independently in the laboratory. Changes in surface topography after thermal shock in many cycles were observed by scanning electron microscopy（SEM）. Changes of three-dimensional morphology and surface roughness were detected by Atomic force microscope（AFM） and the surface hardness was tested after thermal fatigue. The results show that with the increase of the cyclic number, thermal fatigue damage intensifies. The surface of tungsten starts to be molten at 1000 cycles. The surface roughness changes linearly with the cycle number; it is increased firstly and then decreased because of the fatigue hardening.