Effect of in-situ forging assisted squeeze casting on the forming quality and mechanical properties of automobile control arm

Abstract

The squeeze casting technique offers promising prospects for a wide range of applications, as it provides an effective solution to address the challenges associated with the poor casting performance of wrought aluminum alloys. In this paper, we implemented in-situ forging assisted squeeze casting (IFSC) to form an automobile control arm using a high-strength Al–Zn–Mg–Cu alloy modified with Zr and Er. The solidification defects, microstructures, and mechanical properties of the part were investigated under different pressures and in-situ forging using various analytical techniques. With the increase of squeezing pressure from 0 MPa to 120 MPa, the ultimate tensile strength (UTS) of the sample increases from 500 MPa to 593.3 MPa, and the elongation is 4.35 %. After in-situ forging, the tensile strength of the sample is 600.9 MPa and the elongation is 5.59 %. UTS is comparable to squeeze casting, but the elongation is increased by 28.5 %. The results indicate that increasing the forming pressure enhances the surface quality of the parts and reduces the solidification defects. In addition, increasing the forming pressure not only refines the grain but also improves the grain morphology and enhances the uniformity of the structure. The squeezing pressure can enhance the contact between the alloy melt and the mold, increasing the metal's cooling rate and promoting nucleation for grain refinement. In-situ forging further facilitates liquid phase feeding, reduces alloy defects, and improves the overall mechanical properties.