AZ31 마그네슘 합금의 기계적 특성에 미치는 변형속도 및 PB처리의 영향

Abstract

Recently, the world is focused in saving energy and preserving environment. Accordingly, there are also being studied about high strength and light weight material in automobile industry. Magnesium is very effective for weight reduction because its density (1.74 g/cm3) is lower than Al (2.73 g/cm3) and steel (7.85 g/cm3). Therefore, it will be an important part of automobile industry for weight reduction.

The demand for automotive materials with excellent high rate tensile properties is continually increasing in the automobile industry in conjunction with efforts to achieve weight reduction and passenger protection. Until now, researchers have tried to get smooth stress-strain curves and had reproducible mechanical properties such as yield and tensile strength, strain hardening and uniform elongation at high strain rates. Car collision characteristics are evaluated by absorbed energy obtained from the area under stress-strain curves.

In the case of Mg sheet, research mainly focused on the effect of strain rate and temperature on formability, but it is hard to find research for high rate tensile properties. In the present study, the behavior of Mg sheet with strain rates will be observed and the effect of microstructure, texture and PB treatment on high rate tensile properties will be carefully evaluated. The absorbed energy will also be calculated and compared with Al to find out which alloy is better for automotive materials. Strain rate sensitivity calculated from high speed tensile results will be compared with steel and other nonferrous alloys to analyze high rate behavior theoretically, So that the research results offer the basic data to evaluate the applicability of Mg sheet for automotive materials. I also studied fatigue properties with thickness and heat treatment which was called PB treatment.