Effect of Alloying by Sc, Zr and Cr on the Microstructure and Thermal Stability of Al-Mg Alloys

摘要

The structure and mechanical properties of AI-5Mg base alloys alloyed by Sc, Zr and Cr produced by the powder metallurgy method (P/M) and in comparison with traditional method Of casting in water cooled copper chill mould (C/M) are investigated. SEM examination of powders of different alloys showed that the P/M powders had a nondendritic fine-grained Structure with the grain size of 0.5-2 μm. It is shown that Al-Mg base alloys produced by the P/M method are not recrystallized during plastic deformation and subsequent heatings to 550 Celsius. In C/M alloys recrystallization begins already during extrusion. Strength characteristics of the alloyed P/M alloys exceed analogical characteristics of C/M alloys substantially at the high enough level of plasticity of P/M alloys. The ultimate tensile strength of the AI-5Mg base alloys alloyed by Sc, Zr, Cr produced by P/M method ranges from 490 to 506 MPa at plasticity on a level 11.5%.