稀土元素La,Y对钨材显微组织和性能的影响

本文借助金相显微镜、扫描电镜、透射电镜、X射线衍射技术等手段研究了稀土钨加工材的显微组织和性能、稀土第二相粒子在加工和退火过程中的变化规律及稀土钨材的再结晶行为特征。结果表明:稀土元素La,Y的存在强烈地抑制垂熔过程中钨晶粒的长大,而且Y的抑制作用更为显著;随着加工过程的进行,将发生大尺寸第二相粒子的变形和破裂而小尺寸粒子不变形的过程,这一过程将改变第二相粒子在钨基体中的弥散状态,最终影响到钨材的加工性能、再结晶行为及热电子发射性能;此外第二相粒子在高温下的稳定性也是影响材料高温性能、再结晶行为和热电子发射性能的关键因素。

EFFECTS OF RARE EARTH ELEMENTS La AND Y ON MICROSTRUCTURE AND PROPERTIES OF TUNGSTEN MATERIAL

The mechanical properties, the microstructure as well as recrystallization behavior ofthe W-RE (rare earth element) material, and the distribution characteristics of the secondphase particles during processing and after being heat-treated were investigatied by means ofSEM, TEM, X-ray diffraction and microscopy hardness. The results indicate that La and Yhinder drastically the growth of tungsten grains during self-resistant sinter, and the effect ofY is greater than that of La. As deformation of the W matrix continues, the larger secondphase particles deformed and then fractured into segments, but the smaller particles remainrelatively spherical and are not deformed. The consequence of this will change the dispersonmorphology in reference to processing properties, recrystallization behavior and thermoelec-tronic emission. The stability of the second phase at high temperature is a crucial factor thataffects the high temperature properties, recrystallization behavior and thermoelectromicemission of the material.