Semisolid die forging process,microstructures and properties of AZ31 magnesium alloy mobile telephone shells  

作　　者：Ren-guo Guan Li-qing Chen Fu-rong Cao Zhan-yong Zhao Yong Ren 

机构地区：[1]College of Materials and Metallurgy, Northeastern University, Shenyang 110004, China [2]State Key Lab of Rolling and Automation, Northeastern University, Shenyang 110004, China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2011年第6期665-670,共6页矿物冶金与材料学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos.51034002 and 50974038);the New Century Talents Support Program Project of the Ministry of Education of China (No.NCET-08-0097)

摘　　要：A semisolid slurry of AZ31 magnesium alloy was prepared by vibrating wavelike sloping plate process,and the semisolid die forging process,microstructures,and properties of the magnesium alloy mobile telephone shell were investigated.The semisolid forging process was performed on a YA32-315 four-column universal hydraulic press.The microstructures were observed by optical microscopy,the hardness was analyzed with a model 450SVD Vickers hardometer,the mechanical properties was measured with a CMT5105 tensile test machine,and the fractograph of elongated specimens was observed by scanning electron microscopy （SEM）.The results reveal that with the increase of die forging force,the microstructures of the product become fine and dense.A lower preheating temperature and a longer dwell time are favorable to the formation of fine and dense microstructures.The optimum process conditions of preparing mobile telephone shells with excellent surface quality and microstructures are a die forging force of 2000 kN,a die preheating temperature of 250℃,and a dwell time of 240 s.After solution treatment at 430℃ and aging at 220℃ for 8 h,the Vickers hardness is 61.7 and the ultimate tensile strength of the product is 193MPa.Tensile fractographs show the mixing mechanisms of quasi-cleavage fracture and ductile fracture.A semisolid slurry of AZ31 magnesium alloy was prepared by vibrating wavelike sloping plate process,and the semisolid die forging process,microstructures,and properties of the magnesium alloy mobile telephone shell were investigated.The semisolid forging process was performed on a YA32-315 four-column universal hydraulic press.The microstructures were observed by optical microscopy,the hardness was analyzed with a model 450SVD Vickers hardometer,the mechanical properties was measured with a CMT5105 tensile test machine,and the fractograph of elongated specimens was observed by scanning electron microscopy （SEM）.The results reveal that with the increase of die forging force,the microstructures of the product become fine and dense.A lower preheating temperature and a longer dwell time are favorable to the formation of fine and dense microstructures.The optimum process conditions of preparing mobile telephone shells with excellent surface quality and microstructures are a die forging force of 2000 kN,a die preheating temperature of 250℃,and a dwell time of 240 s.After solution treatment at 430℃ and aging at 220℃ for 8 h,the Vickers hardness is 61.7 and the ultimate tensile strength of the product is 193MPa.Tensile fractographs show the mixing mechanisms of quasi-cleavage fracture and ductile fracture.

关 键 词：magnesium alloys semisolid forging microstructure mechanical properties fracture 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG316.3[金属学及工艺—金属材料]