Experimental Study on Semi-solid Squeeze Casting Process of ZL104 Aluminum Alloy Connecting Rod

The filling states, microstructures and mechanical properties of ZL104 aluminum alloy connecting rod prepared by traditional liquid squeeze casting (LSC) and semi-solid squeeze casting (SSSC) processes were investigated. Results show that during the LSC process, the connecting rod is fully filled and its microstructure is a typical dendritic structure. However, its tensile strength and elongation are lower than those of the connecting rod prepared by SSSC process. During the SSSC process, when the pouring temperature is higher than 565 degrees C, the connecting rod is fully filled; the average grain size and shape factor are improved with the increase of the pouring temperature; the tensile strength and elongation are increased first and then decreased. When the squeezing pressure is higher than 25 MPa, the connecting rod is filled fully; with the increase of the squeezing pressure, the average grain size is gradually decreased, the shape factor is gradually increased, and the mechanical properties are gradually improved. Additionally, with the increase of the mould preheating temperature, the average grain size and shape factor are gradually increased, and mechanical properties are gradually improved. However, when the mould preheating temperature is higher than 300 degrees C, the average grain size is further increased and the shape factor is decreased, resulting in the decrease of the mechanical properties of the connecting rod.