Strengthening κ-carbide steels using residual dislocation content

A steel with nominal composition Fe-28Mn-8Al-1.0C in mass percent was hot rolled at two temperatures, 1100 degrees C and 850 degrees C and subsequently aged at 550 degrees C for 24 h. The lower temperature rolling resulted in a yield strength increment of 299 MPa while still retaining an elongation to failure of 26%. The large improvement in strength was attributed to an increase in residual dislocation density which was retained even after the ageing heat treatment. A homogeneous precipitation of kappa-carbides in both samples also showed that the high residual dislocation density did not adversely affect precipitation kinetics. These findings demonstrate that the tensile properties of this class of steel can yet be improved by optimising hot rolling process parameters.

Automated summary

This study investigated the effect of hot rolling temperature on the mechanical properties of a Fe-28Mn-8Al-1.0C steel. It was found that lower temperature rolling significantly increased the yield strength without compromising the elongation to failure. The improvement in strength was attributed to the increase in residual dislocation density, which was retained even after the ageing heat treatment. The homogeneous precipitation of kappa-carbides indicated that the high residual dislocation density did not adversely affect precipitation kinetics.