Deformation behavior of high strength X210CrW12 steel after semi-solid processing

Semi-solid processing of the X210CrW12 hot rolled tool steel resulted in the formation of globular austenitic grains (82.4 vol%) surrounded by eutectic mixture. The thixo-cast steel reached compression strength of 4.8 GPa at plastic strain of 34%. High plasticity was mainly due to high fraction of austenite, its twinning and formation of fine martensite plates during deformation. Additionally, austenite phase contributed to better ductility through preventing growth of cracks initiated within the eutectic areas. Conventional TEM and lattice imaging studies confirmed existence of hexagonal ε-Fe and twins formed during strain-induced transformation.