A double control forming technology combining die casting and forging for the production of Mg alloy components with enhanced properties

A double control forming technology combining the die casting and forging was firstly proposed for the production of Mg alloy components with enhanced properties. In this technology, high-speed filling of liquid melt and high-pressure forging of partially solidified melt were performed by using injection and forging systems of a double control forming device. Some Mg alloy motorcycle wheel components were produced by die casting and double control forming to verify the improvement of the mechanical properties of components formed by double control forming. The results showed that double control forming was an alternative technology for producing the complex Mg alloy components with enhanced properties. Average tensile strength and elongation of Mg alloy components produced by double control forming were greatly improved in comparison with die casting. The average tensile strength was enhanced from 126.8 MPa to 213 MPa and elongation was improved from 3.5% to 7.2%. The optimal process parameters were obtained according to the results of orthogonal experiments, which involved pouring temperature of 675 °C, injection speed of 2 m/s and die temperature of 210 °C. The improved nucleation frequency in the melt caused by the forging pressure led to successful grain refinement of the microstructure of the component produced by double control forming. The defects were removed from the microstructure due to plastic deformation caused by the forging pressure. A refined and densified microstructure led to an enhancement of mechanical properties of Mg alloy component produced by double control forming.