Structural changes and thermal stability of mechanically alloyed Ti-Al powders with additions of Mn and Nb

Abstract

Quaternary Ti-48Al-2Mn-2Nb (at.%) alloys have been prepared by mechanical alloying. The effects of addition of alloying elements (Mn and Nb) on both the structural evolutions during mechanical alloying and thermal stability in the subsequent heat treatment were investigated. Grain size at different milling stages was calculated. The results showed that although the equilibrium solubility of both alloying elements is limited in Al and Ti, Nb was totally dissolved into the matrix of the parent elements before 10 hours of milling, while dissolution of Mn occurred only at later stage of milling. This behavior was mainly due to the difference in mechanical properties between the two alloying elements.