Study On The Forming Process And Mechanical Properties Of Low-pressure Casting Of Magnesium And Aluminum Alloy

Magnesium alloy has attracted great attention in industry because of its low density, high specific strength and rigidity, excellent shock absorption, electromagnetic shielding and casting capability, etc. This article discussed the feasibility of using magnesium alloy to replace conventional aluminum alloy as structural parts.A set of preparing arrangement of low-pressure casting was designed in this paper. Firstly, it introduced the aluminum smelting and low-pressure casting process and got samples. And then, using the device again to carry out the experiment of magnesium alloy and produce samples successfully based on the experimental experience and the requirement of magnesium alloy smelting and low-pressure casting process. Finally, the microstructure and mechanical properties of magnesium and aluminum alloy samples were analyzed respectively.Based on the similarity principle in fluid mechanics, this paper designed a simulator. Using aqueous solution as the analog liquid in the model of organic glass, the process on low-pressure casting cavity fill of molten metal was carried out the research of simulation experiment. The optimal technological parameters of casting process were summarized.Through the above research, main conclusions were drawn as follows:(1) The arrangement could fully meet the experimental requirement, completing the design work preferably.(2) Optimal technological parameters were summarized, such as the applying air pressure Pi, vacuum degree P2, etc. When P1was 0.02Mpa and P2 was-0.02Mpa, parameters of magnesium alloy were the optimal. As for aluminum alloy, the corresponding value was 0.02Mpa and-0.01Mpa respectively. The parameter P1 compared with P2, the former had more obvious affection on the filling time.(3) Through simulation experiment could be found that the liquid surface was almost always maintained the level of state and advanced perpendicularly. It indicated that the air in the cavity and the rising liquid tube was drawn at the same time when vacuuming the mold cavity, making the liquid hardly suffered from the affection of gas back pressure.(4) The displacement-time curve and the speed-time curve in the process of cavity filling were both in line with the expressions of quartic root.(5) Known through the analysis of the mechanical properties (such as tensile strength and tensile stretch, etc), the mechanical properties of aluminum alloy samples in normal temperature were slightly better than magnesium alloy. However, magnesium alloy had the characteristic of higher specific strength than aluminum alloy.