Abstract
Nanostructured Mg alloys have become of interest in various engineering applications due to their high specific strength. The mechanical behavior and microstructure of nanocrystalline (nc) Mg AZ80 alloy, synthesized via a cryomilling (mechanical milling under cryogenic temperature) and spark plasma sintering (SPS) approach are herein reported. First, Mg-based AZ80 powders, with an average grain size of 40 nm were synthesized via cryomilling for 8 hours. Second, the cryomilled AZ80 powder was subsequently consolidated using SPS at 300, 350, 400 and 450oC. SEM and TEM analysis shows that the SPS'ed Mg AZ80 consists of a bimodal microstructure with nc grains and coarse grains. The underlying mechanisms for the formation of bimodal microstructure during SPS sintering and the effect of bimodal microstructure to properties are discussed. A microhardness of 140 HV and a compressive strength of 546 MPa are achieved in the SPS'ed Mg AZ80.