Effect of strain rate and temperature on mechanical properties and fracture mode of high strength precipitation hardened ferritic steels

The effect of strain rate on the flow stress of a low carbon high strength ferritic steel that contains nanometer size Cu–Ni–Al precipitates is found to be much less than that of HSLA 65 that does not have such precipitates. This result is in agreement with the theory that such precipitates locally lower the Peierls stress for screw dislocations in body-centered cubic iron. The fracture mode in the steel is ductile over the wide ranges of strain rate and temperature investigated.