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

Abstract

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 250ºC, and a dwell time of 240 s. After solution treatment at 430ºC and aging at 220ºC for 8 h, the Vickers hardness is 61.7 and the ultimate tensile strength of the product is 193 MPa. Tensile fractographs show the mixing mechanisms of quasi-cleavage fracture and ductile fracture.

Theoretical research on rheological behavior of semisolid slurry of magnesium alloy AZ91D

“…All of these cause low production efficiency and high price of magnesium alloys. How to process magnesium alloys more effectively has become an important subject for the researchers all over the world [1,2]. As an advanced near-net shape processing technique, semisolid metal processing has many advantages such as short forming process, easy formation and good product property; and it has been regarded as an ideal way to process magnesium alloys [1][2][3][4].…”