Mechanisms of creep deformation in a rapidly solidified Al–Fe–V–Si alloy

Abstract

Creep experiments on a rapidly solidified Al-8.5 wt% Fe-1.3 wt% V-1.7 wt% Si alloy (FVS0812) suggest that it exhibits similar or superior deformation resistance compared to other high temperature Al alloys. However, aging at 798 K for 200 h resulted in severe loss of creep strength. Stress reduction results show that FVS0812 exhibits similar creep characteristics to those of other dispersion-strengthened alloys under constant structure conditions following stress reductions, even though the creep mechanism is determined to be significantly different. The operational activation area analysis reveals that the rate-controlling obstacles to dislocation glide are dislocation-dislocation interactions. The role of the particles is to carry a portion of the applied load rather than causing dislocation detachment, local climb, or general climb. This result contradicts the validity of modeling the material using the Rösler-Arzt approach or relying on a threshold stress that is based on the increase in dislocation line length during local or general climb.