Temperature and Strain Rate Dependence of Mechanical Properties and Square Shell Deep Drawability of Al-Mg Alloy Sheets in Warm Working Condition

Abstract

Uniaxial tensile tests and square shell deep drawing tests on 5000 series aluminum alloy sheets were carried out at temperatures ranging from room temperature (RT) to 300°C in order to investigate temperature and strain rate dependence of tensile properties and deep drawability. At these warm working temperatures, tensile strength (TS) decreases with the increase in testing temperature, and this decrease in TS becomes smaller at high strain rate. Elongation (El) is nearly constant in the range from RT to 100°C, but increases largely with the increase in temperature more than 100°C, and this increase in El becomes larger at low strain rate. This change in El mainly depends on local elongation (LEI). Limiting drawing ratio (LDR) of square shell deep drawing in high speed forming becomes slightly bigger than in low speed forming. The change in LDR is small in the temperature range from RT to 150°C. Above 150°C, the LDR value becomes larger, but it becomes smaller in high speed forming. The difference between the LDR value at elevated temperature and that at RT is designated as ALDR value, and this ΔLDR shows the effect of warm deep drawing. The correlation between ALDR and mechanical properties (TS, El, LEI) was investigated and the effective experimental equation was derived.