Surface modification of AZ91 Mg alloy by high current pulsed electron beam irradiation

The cast AZ91 magnesium alloy was surface modified by high current pulsed electron beam (HCPEB) irradiation. The influence of the modification conditions, including but not limited to the accelerating voltage and pulse number on the microstructure and mechanical properties was investigated. The surface modified AZ91 Mg alloy was characterized with optical microscope, scanning electron microscopy, transmission electron microscopy and conventional mechanical probes. The results show that depending on pulse-number, the HCPEB irradiation significantly affects the microstructures and mechanical properties of the alloy. For example, HCPEB irradiation resulted in homogeneous distributions of Mg and Al, and formation of smooth, compact nano-grains by dissolving the coarse dendritic α-Mg and β-Mg17Al12 particles. Moreover, after 8 HCPEB pulsed irradiations at an acceleration voltage of 27 kV, the micro-hardness increased from 62.7 to 119.4 HK; and the wear-rate decreased from 0.01126 to 0.00173 mm3/min. ©, 2015, Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology. All right reserved.