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In this paper, the heat generated during deformation under the static testing of high-manganese TWIP steel with addition of niobium was determined. The research combined the interaction of heat generated during deformation, mechanical properties, hardness and microstructure. Temperature and strain were measured simultaneously using infrared (IR) thermography and digital image correlation (DIC) method. The average temperature measured at the necked region equals 42°C at the strain rate of 0.001 s−1 and exceeds 100°C at 0.5 s−1. Therefore at large strains, a reduction in stress was observed. The course of the hardness change coincides very well with the strain changes, however, at the strain rate of 0.5 s−1 near to the necking area the hardness equals to 360 HV2, whereas at the lower strain rates it equals to 370 HV2. These changes are connected mainly with increase in temperature to >100°C

The material deformation behaviour during the innovative SPD process called DRECE (Dual Rolls Equal Channel Extrusion) has been analysed by FEM simulations. In the process, a workpiece in the form of a strip is subjected to plastic deformation by passing through the angular channel; however, the workpiece dimensions remain the same after a pass is finished. Performing consecutive passes allow for increasing the effective strain in the material to a required level. In the conducted simulations two various channel angles (108° and 113°) have been taken into consideration, as well as two processing routes, A and C (without and with turning the strip upside-down between consecutive passes, respectively). The analysis of simulation results has revealed that significant strain and stress inhomogeneities across the strip thickness are generated in a single DRECE pass. The die design (the inner and outer corner radius) and friction conditions affect the material flow, reducing significantly the shear strain in the near-surface regions of the strip. The strain inhomogeneity can be effectively reduced by choosing the processing route C. The strain distributions and the corresponding tensile test results have confirmed that the smaller channel die angle allows to generate larger strain and higher strength of the strip but also reduces its ductility more than the die setup with the larger channel die angle.