Influence of strain rate on the precipitate microstructure in impacted aluminum alloy

The influence of high strain rate on the precipitate microstructure in impacted aluminum alloy was revealed by transmission electron microscopy. The estimated aspect ratio and the area fraction of θ′ precipitate in impacted aluminum alloy specimens were not dramatically changed until impact testing at 5730 s−1 or higher at ambient temperature although the hardness of specimens impacted at 667–7050 s−1 was decreased. High strain rates are thus a simple way to lower the transformation temperature of θ′ phase in impacted aluminum alloy.