Dynamic behaviour of Al-Mg aluminum alloy at a wide range of strain rates

The effect of strain rate on mechanical properties of Al-2.3wt.%Mg alloy (AA5021) and commercial pure aluminum (purity 99.7wt.%: A1070) was investigated at room temperature. The tensile tests were conducted at strain rates from 1.0×10 −4 to 1.0×10 3 s −1 . The universal testing machine was used for strain rate 1.0×10 -4 to 1.0×10 −1 s −1 . For the strain rate 1.0×10 0 s -1 , the servohydraulic testing machine, which was developed by our laboratory, was used. The impact strain rate 1.0×10 3 s −1 was obtained using the split Hopkinson pressure bar method. The pure aluminum showed positive strain rate dependence of material strength at the investigated strain rates. In contrast, the Al-2.3wt.%Mg alloy showed the negative strain rate dependence at strain rates from 1.0×10 −4 to 1.0×10 0 s −1 . However, Al-2.3wt.%Mg alloy showed the positive strain rate dependence at strain rates from 1.0×10 0 to 1.0×10 3 s −1 . It was surmised that the effect of dislocation locking by the solute Mg atoms became negligible at strain rate of approximately 1.0×10 0 s −1 . It was confirmed that material properties for the Al-Mg alloy at the strain rate of 1.0×10 0 s −1 were important, since the strain rate dependence changed negative to positive around this strain rate.