Research On Preparation And Properties Of Nanocrystalline Magnesium Alloys

Magnesium alloys is the lightest metallic structural material. Due to the unique properties, such as high specific strength and rigidity, easy to recycle and so on, they have great potential for structural applications. However, because of their hexagonal close-packed(hcp) crystal structure, the plastic deformability of magnesium alloys is quite poor at room-temperature, which is an intrinsic drawback to limit their applications. So, enhancing the strength and deformability of magnesium alloy by grain refinement is the key to expand their applications and promote the development of magnesium alloy industry.In this paper, the technology route is―powder-crushing on casting magnesium alloy(AZ31 and ZK60), reactive milling in hydrogen, dehydrogenation and in-situ hot-pressing in vacuum, extrusion and rolling‖. The microstructure of nanocrystalline/ultra-fine grain magnesium alloy was systematically studied with scanning electron microscopy (SEM) and transmission electron microscopy (TEM).The mechanical properties of ultra-fine grain magnesium alloy are studied by tensile test and hardness test equipments.The best technological conditions of dehydrogenation and in-situ hot-pressing in vacuum were used to producing bulk nanocrystalline magnesium, also the mechanical property were investigated. Moreover, to keep grain size of magnesium alloy in nano by the suitable extrusion and rolling process. The nanocrystalline magnesium alloy was fabricated after extrusion and rolling with rational technological conditions, and also its microstructure and mechanical properties were investigated.