Microstructural aspects of energy absorption of high manganese steels

The study presents the results of investigation on two grades of fully austenitic high manganese steels subjected to dynamic compression with usage of the Split Hopkinson Pressure Bar (SHPB). The SHPB test takes only few milliseconds to complete, and during this time it is impossible to transfer the excess heat out of the specimen, therefore the test has to be carried out in adiabatic conditions, and the increase of the temperature caused by the work of plastic deformation must be calculated. Compression behaviour of high Mn-Al-C steel in the solid solution state was correlated to the microstructures developed during plastic deformation in order to clarify the dominant deformation mechanisms. The stacking fault energy of tested steels was between 25 - 50 mJ/m2. The compression behaviour of the steels was manifested by an excellent combination of strength and ductility as well as with continuous strain hardening to the high strain rate. There has been performed a comparison of results of specific energy absorption during dynamic deformation in the same conditions on two grades of MnAl steels. The consequence of continuous work hardening, while perfectly combining strength and ductility, is a great ability to absorb energy of plastic deformation. (C) 2019 The Authors. Published by Elsevier B.V.