Enhancing the crashworthiness of high-manganese steel by strain-hardening engineering, and tailored folding by local heat-treatment

High-manganese twinning induced plasticity steels are a promising alternative for enhancing crashworthiness in automobiles due to their combined high strength and ductility. In this work, we argue that their so-called exceptional tensile strength and ductility are not directly relevant from a component design perspective, but those properties enable tailoring the material response for a given requirement. For this purpose, we compared their crashworthiness with that of an industrial grade steel via drop-tower test. The industrial grade steel performed better although the conventional metrics of crashworthiness predicted otherwise. Then, the crucial effect of strain hardening on the mechanical response of the high-manganese steels is represented by applying two completely different strain-hardening engineering strategies: Recovery annealing and tailored folding. Both approaches enabled high-manganese steel samples to outperform the industrial steel grade ones. Finally, we introduce a new energy absorption metric based on the plastic deformation energy and the deformation volume in order to assess the benefits of the introduced approaches. [Display omitted] •Crash performance of TWIP steels are compared with DP800 industrial steel.•The superior properties of TWIP steels based on tensile data do not infer superior crash performance.•New performance metric is defined for crashworthiness.•Two novel processing strategies improved the performance of TWIP steel crash boxes.