Modification of AZ91 Mg-Alloy with Cu-SiC Particles Wrapped in Graphite and Doped by High Current Pulsed Electron Beams Irradiation

AZ91 Mg-alloy,an advanced aerospace material,was modified with the Cu-SiC particles wrapped in graphite and doped into molten AZ91 by high current pulsed electron beam irradiation.The influence of the doping of Cu-SiC particles and e-beam irradiation on the microstructures and mechanical properties was investigated.The results show that the e-beam irradiation and Cu-SiC doping had a major impact.Specifically,the modified compact AZ91 alloy comprised the dendrite Mg₂Si grains surrounded at the edges by α-Mg and Al₄C₃ clusters; the e-beam irradiation weakened the segregation,improved the uniform distribution and wetting contacts of Cu-SiC particle,refined the grain-size,significantly enhanced the hardness and tensile strength; and the e-beam irradiation of the added Cu-SiC accounted for the formation of Mg₂Si,resulting in the increases of the tensile strength and elongation-ratio of AZ91 Mg-alloy.The ductile and quasi-cleavage modes were the hybrid fracture mechanisms.