기계적 합금화법으로 제조된 Al-10Ti-xSi 합금의 크립 성질

Abstract

The creep properties of the mechanically alloyed Al-10Ti-xSi(x = 0, 2, 4) alloy was investigated in a wide range of stress (50∼310 MPa) and temperature (300∼450℃). The transition of creep mechanism has been observed depending on stress and temperature regimes, i.e. Coble creep at low stresses and temperatures and dislocation creep at high stresses and temperatures. Each creep mechanism could be well explained by using the theoretical Coble creep equation and modified semi-empirical power law dislocation creep equation taking into account of the threshold stress. The transition stress from diffusional creep to dislocation creep becomes higher with an addition of Si. This is due to the comparatively larger threshold stress with an increase of Si content, which was arisen from the increase of elastic modulus as a result of Si incorporation in the Al₃Ti particles. Thus the addition of Si enhances the creep resistance of mechanically alloyed Al-10Ti alloy.