A rate-dependent damage model to characterize dynamic fracture behavior of Ti6Al4V under high strain rate loading

Abstract

Material damage and fracture behavior are affected by loading rates. This paper aims to investigate dynamic deformation and fracture mechanisms of Ti6Al4V over a wide strain rate range from quasi-static to 104 /s. A high strain rate test apparatus is developed and a new rate-dependent material damage law is proposed. The damage energy of Ti6Al4V keeps nearly constant at the strain rate lower than 10 /s, while it declines dramatically under the strain rate high than 103 /s. Ductile to brittle transition of Ti6Al4V occurs at the strain rate of 16,000 /s, which leads to the transition of material fracture mechanism from adiabatic shear to embrittlement fracture. The research proves that developing appropriate damage evolution law is important to improve prediction accuracy of material deformation and guarantee structural design safety especially for dynamic loading components.