급냉분말야금법으로 제조한 Al - Fe - V - Si - Ti - W 합금의 고온크립거동

Abstract

The elevated temperature creep properties and microstructural stability of RS/PM Al-10Fe-1.3V-2Si-1Ti-1W(wt.%) alloy have been investigated. The alloy showed high stress exponent of 12 to 18 and activation energy of 237 to 808 kJ/㏖, which was strongly dependent on the temperature and stress. The unusual creep behavior of the dispersion strengthened alloys cannot be described satisfactorily by current creep laws, Recently, Ro¨sler and Arzt proposed a new model assuming thermally activated dislocation detachment from dispersoids exerting an attractive force. In the present study, experimental evidence was achieved for the presence of attractive interaction between the dislocation and the dispersoids using TEM observations. The creep behavior of the alloy was analyzed using the model proposed by Ro¨sler and Arzt, and the experimental data were consistent with the prediction based on the model. It has been confirmed that the high temperature deformation of the alloy was dominated by the dislocation creep at the temperature range of 400 to 480℃, but the diffusional creep at the interface between powders also contributed to the deformation above 430℃.