机械合金化Nb-Cr粉末的热力学分析

在球、料质量比为13∶1的条件下对Nb-Cr二元粉末进行了高能球磨,研究了摩尔比为1∶2的Nb、Cr混合粉末的机械合金化（MA）过程,用X射线衍射（XRD）分析了球磨粉末的物相组成.结果表明,球磨20 h后粉末变化为先形成Nb（Cr）的过饱和固溶体,45 h后逐步形成非晶,进一步球磨,159 h后发生非晶的晶化.参考Miedema半经验模型理论,建立了Nb-Cr系MA过程的热力学模型.该模型的计算结果表明,Nb-Cr二元系具有形成非晶、固溶体和化合物的热力学驱动力.对摩尔比为1∶2的Nb、Cr混合粉末不同时间XRD结果进行了分析,发现与热力学计算结果吻合.

Thermo-kinetic Analysis of Mechanical Alloying Nb-Cr Powders

The mechanical alloying process of Nb and Cr mixed powder(1:2 in molar ratio) has been analyzed by high energy ball milling for Nb-Cr binary alloy powder in case of the mass ratio of steel ball to powder of 13:1,and the phase constituent of the Nb-Cr powders has been observed by XRD(X-ray diffraction).The results reveal that firstly,the Nb(Cr) solid solution phase can be formed with ball milling for 20 h,then amorphous phase appears after 45 h,further,the crystallization of amorphous phase occurs for 159 h.The thermo-kinetic model of mechanical alloy process of Nb-Cr series has been established by referring to the Miedema semi-empiric theory to describe the phase transformation of Nb-Cr system during milling.The thermo-kinetic simulation verifies that the Nb-Cr binary system possesses thermo-kinetic driving force forming amorphous phase,solid solution phase and compound.The simulated results are well in agreement with the XRD analysis ones.