Abstract: The surface hardness and wear resistance of aluminum alloy are both improved by means of scanning electron beam. Surface modification of the aluminum alloy with electron beam scanning is studied. The effects of electron beam parameters such as power density, scanning frequency and scanning time on the surface strengthening layer of aluminum alloy are discussed. The influence of electron beam scanning on the microstructure and property of strengthening layer is studied. The reason for cracks on the specimen in the process of electron beam surface treatment is discussed. Microstructure of electron beam surface strengthening layer of aluminum alloy is analyzed by using scanning electron microscope, and the compositions are detected by using EDS. The hardness and wear resistance of aluminum alloy surface are tested by using HMV-ZT Rockwell hardness tester and HT - 500 friction and wear tester respectively. The experimental results show that the depth and width of the strengthening layer increase with increasing of the power density and scanning time, but the effects of scanning frequency is insignificant. The crystal grain in the strengthening layer is highly refined after electron beam scanning. The hardness of surface strengthening layer is 1.39 times that of matrix structure. The wear resistance is improved obviously. The contraction stress produced in the solidification process is the main reason for cracks on the specimen.

Key words: Aluminum alloy, Electron beam, Hardness, Wear resistance