Improvement of wear resistance of AZ31 and AZ91HP by high current pulsed electron beam treatment
(1. School of Materials and Metallurgy, Northeastern University,
Shenyang 110004, China;
2. State Key Laboratory for Materials Modification by Laser, Ion and Electron Beams, Department of Material Science and Engineering, Dalian University of Technology, Dalian 116024, China)
Shenyang 110004, China;
2. State Key Laboratory for Materials Modification by Laser, Ion and Electron Beams, Department of Material Science and Engineering, Dalian University of Technology, Dalian 116024, China)
Abstract: The surface modification of magnesium alloys (AZ31 and AZ91HP) was studied by a high current pulsed electron beam(HCPEB). The results show that the cross-sectional microhardness of treated samples increases not only in the heat affected zone(HAZ), but also beyond HAZ, reaching over 250μm. This is due to the action of quasi-static thermal stress and the shock thermal stress wave with materials, which result in its fast deformation on the surface layer and so increases microhardness. For the AZ91HP alloy, a nearly complete dissolution of the intermetallic phase Mg17Al12 is observed, and a super-saturated solid solution forms on the re-melted surface, which is due to the solute trapping effect during the fast solidification process. Measurements on sliding wear show that wear resistance is improved by approximately 5.6 and 2.4 times for the AZ31 and AZ91HP respectively, as compared with as-received samples.
Key words: magnesium alloys; wear; high current pulsed electron beam(HCPEB)