In-situ processing and aging behaviors of MgAl2O4 spinel whisker reinforced 6061Al composite

6061 aluminum-alloy matrix composites are drawing greater attention due to their low density, excellent mechanical properties and wear resistance. In this study, in-situ generated MgAl2O4 spinel whiskers reinforced 6061Al alloy matrix composites were fabricated and solutionizing and age hardening treatment was performed on the composites in a temperature range of 160-210 °C. The microstructure and mechanical properties of the composite were investigated and the influences of in-situ generated whiskers on aging behaviors of the composite were also discussed. The results show that the whiskers exhibit a homogeneous distribution with good interface bonding with the matrix. The hardness and ultimate tensile strength (UTS) increase with increasing content of the whisker, whereas the ductility decreases at the same time. The properties of the composites attained a peak value of 195 HV in hardness and 400 MPa in UTS after aging for 30 min at 190 °C. Compared with the 6061Al alloy, the presence of whiskers could accelerate the aging kinetics of composites due to the high density dislocations formed during the fabrication process.