Melt Mixing Process And Overheating Deterioration The Za27 Alloy Microstructure And Properties Of The Impact

Zn-Al alloy is widely used as a new type of metal material. Zn-Al alloyhas a lot of advantages, such as high strength, high hardness, excellent wearresistance performance, low production cost.Meanwhile, Zn-Al alloy also hasthe characteristics of low melting point, less energy consumption, formingconvenient, applicable for various casting method. In Zn-Al alloy, ZA27alloyhas the most excellent performance,but ZA27alloy also has somedisadvantages like other Zn-Al alloy, such as plastic toughness is bad, thework temperature is low, corrosion resistance is bad etc.In this paper, the meltmixing and overheating metamorphic were used to process the ZA27alloy.Through the orthogonal design method arrange all experiment, theexperimental results were analyzed and identify the intensitied of eachaffecting factor and the best combination method.1.The effect of melt mixing treatment on the microstructures andmechanical properties of ZA27alloy was studied by the method of orthogonaltest and determine the optimum combination of high temperature melt andlow-temperature melt.1). Mixing melt treatment can obviously improve the mechanicalproperties of ZA27alloy, refining cast structure of alloy. When the temperatureof high temperature melt is720℃, the temperature of low temperature melt is500℃, ZA27alloy comprehensive mechanical performance is best. Thehardness of alloy with treatment is122.5HB,increased10.66%than the alloywithout treatment.2). Mixing melt treatment can obviously refine cast structure of alloy ofZA27alloy, Appropriate treatment can change cast microstructures from thedendritic to the petals shape.3).Variance analysis shows: Influence factors of the treatment are thetemperature of high temperature melt,interaction of high and low melttemperature. The temperature of high temperature melt has a remarkableremarkable effect; interaction of high and low temperature have some influence;low temperature melt mainly through the impact of high temperature melt to influence the result of the experiment.2.The effect of overheating metamorphic on the microstructures andmechanical properties of ZA27alloy was studied by the method of orthogonaltest. Influencing factors in the experiment are the amount of metamorphic,overheating temperature and over-temperature holding time, determine thefactors affect the strength of the alloys, and to determine the optimumexperimental combinations.1).Overheating metamorphic can obviously improve the mechanicalproperties of ZA27alloy. When the dosage of rare earth is0.2%, overheatingtemperature is780℃,when overheating holding time is10min, the alloy hasthe best performance. At this time the hardness of alloy is110.5HB, impacttoughness is20.5j/cm~2; Impact toughness increased81.26%than the alloywithout treatment.2).Overheating metamorphic can obviously refine cast structure of ZA27alloy. Appropriate treatment can make the edge of cast microstructures to beglobularity and refine cast structure of alloy.3).Variance analysis shows: The influence of rare earth amount on thehardness of ZA27alloy is very important,and the overheating temperature isimportant too, but the influence of holding time is not significant. The influenceof overheating temperature on the toughness of ZA27alloy is verysignificant,and the amount of rare earth is significant, while the influence ofholding time is not significant.