CYCLIC DEFORMATION AND LOW-CYCLE FATIGUE BEHAVIOR IN A SICW 6061AL COMPOSITE AT ELEVATED-TEMPERATURE/

The cyclic deformation and low cycle fatigue behavior of a SiC whisker reinforced 6061 aluminum alloy matrix composite were investigated at elevated temperatures with total strain controlled method. TEM and SEM were used to examine the microstructure and fracture surfaces of the specimens. The mechanical test results demonstrated that the composite materials maintained initial cyclic hardening at the elevated tempera ture. The fatigue resistance to cyclic strain of the composite was fou nd to be inferior to that of the matrix material in the total strain c ontrolled testing, while the composite material showed superior fatigu e strength in the low cycle fatigue region within the temperature rang e in the present research. The fatigue failure of the composite is bel ieved to be caused by a mechanism of nucleation, growth and coalescenc e of voids.