Effect of Process Parameters on the Mechanical Properties and Microstructure of Large-Sized Aluminum Alloy Parts with Complex Shape Formed by Squeeze Casting

In this paper, engine flywheel shell components of ZL104 aluminum alloy were formed by squeeze casting forming technology, and the effect of process parameters on mechanical properties and microstructure of the formed parts was investigated. Sixteen sets of orthogonal test schemes are designed according to four conditions of specific pressure, holding time, pouring temperature and mold temperature. After the mechanical properties of the castings under different sets of experimental conditions were analyzed, the optimum process parameters were derived from the comprehensive analysis according to tensile strength and elongation. The optimum process parameters involve a casting temperature of 655 °C, a scheme B mold temperature, a pressure holding time of 20 s and a specific pressure of 34 MPa. The average tensile strength and average elongation of the formed flywheel shell components under the optimum process conditions were 211.2 MPa and 7.7%, respectively. The microstructure of the formed parts is mainly composed of α-Al phase and eutectic silicon phase. When the process parameters are properly selected, high mechanical properties and microstructure with little cast defects were obtained in the parts formed by squeeze casting. Except for Al, Fe, Mn and Si elements are mainly enriched at the grain boundary.