Effect of laser surface melting on high temperature tensile properties of AZ91D magnesium alloy

Laser surface melting was used to treat the surface of a magnesium alloy for improving the mechanical behavior at elevated temperatures. The results revealed that grain refinement and enhanced microhardness are obtained by LSM treatment. The tensile test results at room temperature and elevated temperatures indicated that strength of LSM treated sample increases compared with as-received sample, while ductility decreases. Fractography indicated that ductile mode was the fracture characteristic of laser melted zone at room and elevated temperatures. Non dynamic recrystallization in the laser melted zone, fracture crack deflection and stress transfer were responsible for the increased strength of LSM treated sample at elevated temperatures.