A study on rate sensitivity of elasto-plastic fracture toughness of TRIP steel evaluated by a small punch test

Abstract

Abstract. TRIP steel indicates an excellent characteristic in energy absorption because of its high ductility and strength by strain-induced martensitic transformation (SIMT). Recently, some shock absorption members are being used for automotive industries. For good fuel consumption of the automobile, it would realize the weight reduction without decaying performance if TRIP steel can be applied to those members. It can be considered that the fracture toughness is an important factor to evaluate the performance. To evaluate fracture toughness locally at any point of a product of those members, small punch testing method is quite effective. In the present study, first, an impact small punch testing apparatus is established. In addition, elasto-plastic fracture toughness of TRIP steel under impact loading and its rate sensitivity tested at various deflection rates are challenged to evaluate.