Narrow Results

The microstructures and mechanical properties of as-cast Mg-Zr-Ca alloys were investigated in this study for potential use in biomedical applications. The Mg-Zr-Ca alloys were fabricated by commercial pure Mg (99.9 mass%), Ca (99.9 mass%), and master Mg-33mass%Zr alloy. The microstructures of the alloys were examined by X-ray diffraction (XRD) analysis and optical microscopy (OM), and the mechanical properties were determined from tensile tests. The experimental results indicate that an increase of Zr obviously increases the strength of Mg-Zr-Ca alloys with 1 mass% Ca and the formation of Mg₂Ca decreases the strength of the alloys. Mg-1Zr-1Ca alloy (mass%) has the highest strength and best ductility among all the studied alloys.

To obtain the low plasticity aluminum alloy connecting rods with good quality, a casting-forging process was put forward in this study. Firstly, the process feasibility of Al-Si-Cu alloy was analyzed by its chemical composition and plasticity chart, and according to the analysis results the casting-forging process was given. Secondly, to solve the crack defect of forging with initial shape of casting billet, an improved shape of casting billet was determined based on divided-flow method. Finally, the wear resistance, mechanical properties and metallographic microstructures of the connecting rods were investigated in details by various tests. Compared with casting, the casting-forging process could improve the wear resistance. The wear resistance of Al-Si-Cu alloy casting-forging connecting rod was better than the other two aluminum alloy forging connecting rods. The tensile strength and elongation of casting-forging process were larger than casting process. The microstructures well explained the performance improvement of the casting-forging connecting rod.