Energy absorption and dynamic behaviour of 6xxx series aluminium alloys: A review

This document reviews the recent research work on the mechanical properties of 6xxx series aluminium alloys at strain rates in the range of -10-5 - 105 s-1, and crashworthiness of tubes made of 6xxx series aluminium alloys under dynamic loadings (mass impact). This review endeavours to accentuate the material response (fracture toughness and dynamic stress-strain curves) at high strain rates and structural (collapse behaviour of tubes) response under quasi-static and dynamic loadings. Though this review is primarily focused on dynamic prop-erties and behaviour, quasi-static data is also reviewed as the benchmark to distinguish the dynamic effect. Over the past few years, there had been a broad range of research publications dealing with the dynamic behaviour of 6xxx series Al alloys processed through various thermo-mechanical routes. Many papers have reported the fracture toughness measured through Charpy and Izod tests. A major portion of the research work has been dedicated to characterize the dynamic stress-strain curves obtained from tests using split-Hopkinson pressure bars, and to measure the strain rate sensitivity. Many studies cover analytical and numerical approaches for modelling of material responses at varying strain rates as well. This review analyses the effects of sample processing routes and heat treatments (at elevated, sub-zero and cryogenic temperatures) on dynamic behaviour of the Al alloys.This work also focuses on correlation of material response with microstructural features to ascertain the effects of crystallographic texture and microstructure on energy absorption and dynamic failure modes observed during dynamic testing. In addition, this paper also includes a review of structural response of tubes under dynamic compression. Analytical and numerical models have been included wherever available. The research gaps have been identified for future investigations.