机械球磨Al-10%Ti粉末的组织和热稳定性

Microstructure and Thermal Stability of Mechanically Milled Al-10%Ti Powder Mixture

研究了机械球磨方法制备的Al-10%Ti 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;Al-10%Ti 混合粉末反应烧结后相互扩散形成的最终产物是DO22-Al3Ti。

In order to search a new process of fabricating TiAl intermetallic compounds with favorable combination of properties, this paper investigated the microstructure and thermal stability of Al-10wt.%Ti powders synthesized by mechanical milling. The experimental results show that Al, Ti particle and grain size decrease rapidly with the increase of milling time, and that the more 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, hence raise the internal energy and the diffusivity. The final equilibrium phase of Al-10wt.%Ti powder which was sintered is DO22-Al3Ti.