Research On ZM5 Magnesium Alloy Separator For Indirect Extrusion Casting To Form Mine Casing

Magnesium alloy has many excellent properties such as low density,good seismic performance,high specific strength,high specific stiffness,good recyclability,etc.It has great application prospects in the fields of aerospace,automotive parts and military defense.However,the magnesium alloy prepared by traditional casting process has inherent casting defects caused by technical characteristics,which makes it difficult to produce structural parts with different functions.Extrusion casting is a near-net forming technology,which can be used to prepare magnesium alloy products to reduce macroscopic defects and obtain good mechanical properties.The basic principle of indirect extrusion casting process is to apply the extrusion pressure on the metal liquid at the sprue through the punch,and the metal liquid at the sprue will transfer the pressure to the metal liquid in the mold cavity,so that the metal liquid in the mold cavity will be solidified and formed under higher pressure,indirect extrusion casting is suitable for the production of castings with certain shape and structure.Indirect extrusion casting is suitable for the production of castings with certain shapes and structures.In this paper,we take ZM5 magnesium alloy spacer for mine shell as the object of research,and carry out research work on three aspects:simulation of forming process of spacer,indirect extrusion casting experiment of spacer and heat treatment process of spacer.In this paper,a three-factor,three-level orthogonal test was designed for the three most influential process parameters in the extrusion casting process:pouring temperature,specific pressure and holding time.Pro CAST software was used to simulate the filling process and solidification process of ZM5 magnesium alloy spacer parts under nine groups of different process parameters.The nine groups of process parameters were analyzed and compared by defect field,temperature field and solidification field,and the optimal process parameters were derived.The simulation results show that all the 9 groups of process parameters have complete filling,and the shrinkage and shrinkage holes mainly exist in the round boundary wall thickness of the spacer.According to the designed orthogonal test scheme,indirect extrusion casting experiments were carried out to analyze the microstructure and mechanical properties of the nine produced ZM5 magnesium alloy spacer parts.The study shows that there are obvious differences in mechanical properties of ZM5 magnesium alloy spacer parts produced by different process parameters,based on tensile strength and elongation,the optimal process parameters are:pouring temperature 700?,specific pressure 130Mpa,holding time 30s,which are derived from the simulation and orthogonal test.The average tensile strength is 180.49Mpa,the average yield strength is 94.89Mpa,and the average elongation is 5.71%.The microstructure is mainly composed of?-Mg matrix and the second phase Mg₁₇Al₁₂,with less dendritic crystals,and the extrusion casting process has a certain crushing effect on the dendritic crystals.For the study of the heat treatment process using the controlled variable method,the ZM5magnesium alloy spacer parts were studied for the solid solution process and aging process respectively,and the corresponding better process parameters were determined through experiments.The research shows that:the solid solution treatment on the mechanical properties of ZM5 magnesium alloy spacer is more obvious,tensile strength and elongation significantly increased,while the yield strength will appear a certain degree of decline;compared with the solid solution treatment process,the aging treatment of ZM5 magnesium alloy spacer tensile strength increased less,yield strength increased,elongation seriously decreased.The better process parameters were determined as follows:solid solution temperature of 410?,solid solution time of 20h;aging temperature of 200?,aging time of 8h.The average tensile strength of ZM5 magnesium alloy spacer was 228.37MPa,average yield strength was 91.49Mpa,average elongation was 7.3%when the solid solution treatment process parameter was410?×20h;the aging treatment process parameter was The average tensile strength of ZM5magnesium alloy spacer at 200?×8h is 242.49Mpa,the average yield strength is 120.8Mpa,and the average elongation is 3.9%.Considering the comprehensive performance,the solid solution treated ZM5 magnesium alloy spacer parts will be more suitable for practical use.