Effect Of Heat Treatment On Properties Of As-cast AM50 Magnesium Alloy

Many researchers are interested in magnesium alloys due to its many advantages including low specific gravity, high specific strength, specific rigidity, damping process ability, excellent electromagnetic shielding and recyclability. The exploitation of magnesium alloys series with excellent properties is the mostly trend currently. But it is effective way that magnesium alloys in existence are appropriately technical processed.It is an effective method of improving the properties of material by heat treatment. So that is an effective intendency to investigate the effects of heat treatment on the microstructures and properties of AM50 die-cast magnesium alloy. This is used in AM50 die cast magnesium alloy in this paper in order to improve material’s microstructure and enhance its properties. Research on influence of solution and aging heat treatment on microstructure and hardness and corrosion properties of die-cast AM50 magnesium alloy were systemically studied in this paper by OM, SEM, XRD as well as hardness, corrosion experiments. The results showed that :The β-Mg17Al12 phase discontinuously distributed along the grain boundary was dissolved into α-Mg matrix through the solution treatment. With longer time at solution treatment, the hard β-Mg17Al12 phase existed continuously at grain boundaries of α-Mg phase, it precipitates at α phase dispersedly instead of precipitating at grain boundaries and the properties of the alloy are improved more distinctly. But the grain was too big and the properties getting worse if the time was too long. With longer time at solution treatment,the hardness of alloy improved first, then decreased. The corrosion resistance of die-cast AM50 magnesium alloy decreased at first, then improved after longer solution time. In this paper alloy has better properties after solution treat16 h. It’s better method to cold alloy in water after solution treatment.The aging treatment after solution treatment makes β-Mg17Al12 phase occur with discontinuous and continuous precipitation from oversaturated α-Mg solid solution. The hardness of alloy improved with longer time at aging treatment. The corrosion resistance of die-cast AM50 magnesium alloy decreased after longer aging time.In this paper alloy has better properties after aged 30 h. It’s better method to cold alloy in air after aging treatment.