Researches On Deformation, Microstructure And Properties Of The New Magnesium Alloy

With its light weight, nice vibrate resistance, great electromagnetic shieldingability and many other advantages, magnesium alloys, which are the new trend in thedevelopment of the global light metal materials, are widely used in the field ofaerospace, military electronics, automotive, high-speed rail and other areas. However,the low intensity(≤280MPa), poor toughness(≤10%) and poor corrosion resistanceare the key technological bottlenecks which severely restricted the development ofmagnesium alloy. Through lucubrating deformation mechanism of the newmagnesium AZ33M, this paper revealed the relationship between the strength,toughness and forming. In addition, the primary cause of low strength and poortoughness of common magnesium alloys—the occurrence of dynamicrecrystallization and formation of rigidity dislocation networks—were also found.the industrial application and development of magnesium alloys are. Research showedthat compared with common magnesium alloys,AZ33M magnesium alloy extruded at300℃had the best room-temperature mechanical properties, which tensile strength,yield strength and elongation reached340Mpa,281Mpa and17.24%respectively.The results found that the mechanical properties of the types of AZ and ZKmagnesium alloys had been changed when the extrusion processes were different. Byand large, in the extrusion process, the tensile strength and yield strength decreased asthe temperature increased, while the elongation presented the tendency that firstincreased, then reduced.Microstructures extruded at different temperatures indicated that AZ31andZK60magnesium alloys occurred different level of dynamic revrystallization at300℃, while AZ33M magnesium alloy still stayed in the state of strain hardening,which the dynamic recrystallization temperature was350℃.Dynamic recrystallization is an important mechanism of softening. Althoughdynamic recrystallization can greatly increase the plastic of materials while it can alsoreduces the strength of the material. The nucleation mechanism of dynamicrecrystallization is not the same at different extrusion temperature. The overall trend of nucleation mechanism is when the extrusion temperature increases, atomic thermalvibration and diffusion rate of magnesium alloys rises. Compared with low extrusiontemperature, dislocation slip, climb cross-slip and nodes of is easier. So the ratio ofdynamic recrystallization nucleation increases which can promote the occurrence ofdynamic recrystallization.The new magnesium alloy AZ33M tested pilot-scale production in ChengduQingyuan Magnesium Science&Technology Co., Ltd. In the process of industrialproduction, the reasonable extrusion process to ensure the surface quality ofproduction is that extrusion temperature≤300℃, extrusion speed≤2mm/s.