Microstructure and mechanical properties of AZ31B magnesium alloy recycled by solid-state process from different size chips

AZ31B magnesium alloy chips of different size were recycled by hot extruding. Mechanical properties and microstructure of the recycled specimens and reference specimen were investigated. Amounts of oxide in recycled materials were estimated. Almost all the recycled specimens exhibit higher strength than reference specimens, this is mainly attributed to grain refinement strengthening whereas particle-dispersion strengthening has few effect. The strength of recycled specimen increases with increasing of total surface area of chips because of different grain size. Recycled specimens show inferior ductility than reference specimens and recycled specimens with medium surface area of chips possess highest elongation. Grain size, oxide amount and density of billet have an effect on the elongation of recycled materials.