球磨工艺对原位合成纳米级TiB的影响

Effect of ball milling process on the in situ synthesizing of nano-TiB whiskers

摘要:

球磨工艺对球磨粉末及其烧结组织的微观结构和形态都有重要的影响。本实验采用低能和高能球磨两种方式对Ti-Al-0.2B wt.%合金粉末进行球磨,研究球磨过程中粉末组织和形态的变化,并将球磨后的粉末进行热压烧结,研究不同球磨方式对烧结组织中原位合成TiB增强相形态的影响。研究结果表明：低能球磨过程中粉末颗粒间有机械合金化发生,其烧结组织中生成的TiB为细长态,在基体中分布均匀,没有联结的粗晶或成簇生长现象。对于高能球磨,粉末颗粒细化效果明显,颗粒平均尺寸降至1 μm,球磨过程中除了机械合金化还形成了Ti(Al)过饱和固溶体,并在球磨后期形成了非晶结构。经高能球磨的粉末烧结后,组织中生成了均匀分布的纳米级TiB晶须。

Abstract:

Ball milling process has an important effect on the microstructure of final powder products and the corresponding as-sintered samples. In this study, Ti-Al-0.2B wt.% mixed powders were ball-milled by low-energy and high-energy types of ball mills, and then the milled powders were sintered by hot- pressing. On this basis, morphology evolution of the powders was analyzed, and the microstructure of the reinforcements in the as-sintered composites was investigated. In the low-energy ball milling process, mechanical alloying was occurred between the powder particles. TiB whiskers formed in sintering process were long and thin without coarse bars or clusters. For the high-energy type, the particle size was refined remarkably to 1um, and Ti (Al) supersaturated solid solution or even amorphous structure was formed during the milling process. In the following sintering process, nano-scale TiB whiskers were synthesized and they were uniformly distributed in the matrix.