机械球磨作用下Al/Ti混合粉末的组织和热稳定性

Microstructure and thermal stability of mechanically milled Al/Ti mixed powders

为探索一种制备高综合性能Al Ti基金属间化合物的新方法 ,研究了机械球磨方法制备的Al -1 0 %Ti(质量分数 )混合粉末的组织和热稳定性。结果表明 :在球磨作用下 ,Al、Ti粉末的颗粒尺寸得到有效细化 ,并且球磨时间越长 ,Al/Ti粉末储备能量越大 ,生成Al Ti金属间化合物所需的反应激活能越低 ,内能的增加和扩散能力的提高是由于机械球磨导致了大量的晶格缺陷 ;经 90h球磨的粉末在 6 6 0℃下经 6h热处理后生成Al3 Ti,还有少量的Al2 Ti,Al5Ti2

In order to search a new process of fabricating Al-Ti intermetallic compounds with favorable combination of properties, the microstructure and thermal stability of Al-10wt%Ti powders systhesized by mechanical milling was investigated. The experimental results show that Al, Ti particle and grain size decrease rapidly with the increase of milling time, and that the longer milling time, the more energy stored in the composite powders. Consequently, the activation energy of the reaction for Al-Ti intermetallics decreases obviously. It is mechanical milling that causes a large number of crystal defects such as dislocations, vacancies, stacking fault and grain boundaries so as to raise the internal energy and enhance the diffusivity. Al3Ti and a little Al2Ti and Al5Ti2 are formed after the powder is milled for 90 h and heat treated at 660°C for 6 h.