Ta-Al粉末的机械合金化制备及球磨工艺优化

Mechanical Alloying Preparation and Ball Milling Process Optimization of Ta-Al Powder

通过设计正交实验确定最佳球磨工艺,并利用优化工艺对Ta-Al混合粉末进行机械合金化,以XRD和SEM法研究了球磨时间和组分变化对Ta-Al合金化过程的影响。结果表明,球磨时间对晶粒细化影响最为显著,而固液比在本实验范围内对其影响较小。综合分析考虑最佳球磨工艺组合为:球料比10∶1、固液比1∶0.5、球磨转速300r/min、球磨时间36 h。Ta-Al体系经高能球磨8 h后,基本实现合金化,部分Al扩散固溶入Ta中,形成置换固溶体,继续球磨衍射峰宽化、峰强降低。当Ta-10wt%Al时,检测不出Al衍射峰,呈单相结构,经计算28.9at%Al在热力学和动力学共同驱动下固溶入Ta中形成过饱和固溶体,剩余Al弥散分布在Ta的纳米晶界处。

The optimum ball milling process was determined by orthogonal design,and Ta-Al mixed powder was mechanically alloyed by optimized process.XRD and SEM were used as the main characterization methods to study the effect of ball milling time and composition change on Ta-Al alloying process.The results show that the ball milling time has the most significant effect on the grain refinement,while the solid-liquid ratio has less influence on the experimental range.The comprehensive analysis considers the best ball milling process combination:ball to material ratio 1o:1.The solid-liquid ratio is 1:0.5,the ball milling speed is 300r/min,and the ball milling time is 36 h.After high energy ball milling for 8 h,Ta-Al system is basically alloyed.Part of Al diffuse into the Ta to form a replacement solid solution,and continue to ball mill diffraction peak broadening and peak strength reduction.When Ta-1owt%Al,no Al diffraction peak is detected,and the single-phase structure is obtained.After calculation,28.9at%Al is solid-dissolved into Ta under the combined driving of thermodynamics and kinetics to form a supersaturated solid solution,and the remaining Al is dispersed in the nanocrystalline boundary of Ta.