Dynamic compression behavior of 6005 aluminum alloy aged at elevated temperatures

Abstract

In this study, relationship between dynamic compression behavior and microstructure of 6005 aluminum alloy artificially aged at elevated temperatures in the range of 180 °C to 330 °C for 0.5 h was investigated. Dynamic compression response at strain rates from 1200 s−1 to 2700 s−1 was studied using a modified split Hopkinson pressure bar system. It was observed that aging temperature has profound influence on generation of microstructure and resulting properties of the alloy. It is widely known that an increase in hardness of Al-Mg-Si alloys results with increase in aging temperature and aging time. This can be attributed to the formation of dense population of metastable β'' precipitates in the microstructure of peak aged Al-Mg-Si alloys. Energy absorption was observed to increase while there was no obvious change in the dynamic stress strain behavior with increasing strain rate. However, dynamic stress-strain behavior exhibits an evident dependence on aging temperature which has an influence on the initial microstructure. At constant strain rate, homogenously distributed fine needle like β'' precipitates were observed in the alloy aged at 280 °C. This alloy exhibits higher strength but lower energy absorption in comparison with the alloys aged at other temperature. Results show that dynamic stress-strain behavior is sensitive to precipitates while aging at 280 °C for 0.5 h is sufficient for obtaining excellent precipitation strengthening and better energy absorption ability under dynamic compression.