Microstructure Evolution and Mechanical Properties of As-Cast Pb-Mg-Al Alloys

In this study, two new types of Pb-Mg-Al alloys with high tensile strength and hardness were prepared by casting under the molten salt. The microstructure and morphology of the Pb-Mg-Al alloys were investigated through x-ray diffraction and scanning electron microscope analysis. Mechanical properties of the alloys were compared with those of the pure Pb and its alloys, and the results indicate that the tensile strength and hardness increase, respectively, up to 300 MPa and 156 HB with the 10 wt.% addition of Al. The fractographic examinations indicate that the fracture model of Pb-Mg-Al alloys changes from mixed intergranular-transgranular to the intergranular quasi-cleavage with the increase in Al content.