Thresholds in creep of magnesium alloy AX41 composites reinforced with short fibers

Abstract

Abstract Creep behavior of four magnesium Mg-4Al-1Ca alloy-based composites reinforced with short alumina or carbon fibers was investigated at temperatures 423, 473, 523, and 623 K. The threshold creep behavior was observed in all composites as well as in the matrix alloy AX41. Both types of fibers strongly increase creep resistance of the composites. A stronger strengthening effect was observed in composites with alumina fibers. The applied stress dependences of the minimum creep rate of all investigated materials were well described by Garofalo' sinh relationship modified for threshold concept. Threshold stresses and their temperature dependences were evaluated from the stress dependences and discussed in detail from the viewpoint of contemporary knowledge of mechanisms governing the creep behavior of metal-matrix composites.