The low-carbon steel (~0.12 wt%) with complete martensite structure, obtained by quenching, was cold rolled to get the high-strength steel sheets. Then, the mechanical properties of the sheets were measured at different angles to the rolling direction, and the microstructural evolution of low-carbon martensite with cold rolling reduction was observed. The results show that the hardness and the strength gradually increase with increasing rolling reduction, while the elongation and impact toughness obviously decrease. The strength of the sheets with the same rolling reduction are different at the angles of 0°, 45°, and 90° to the rolling direction. The tensile strength (elongation) along the rolling direction is higher than that in the other two directions, but the differences between them are not obvious. When the aging was performed at a low temperature, the strength of the initial martensite and deformed martensite increased with increasing aging time during the early stages of aging, followed by a gradual decrease with further aging. However, the elongation increases with increasing aging time. The change of hardness is consistent with that of strength for the cold-rolled martensite, while the hardness of the initial martensite decreases gradually with increasing aging time.

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In this work, thermal deep drawing and thermoelectric coupling drawing tests were performed on an annealed ZK60 magnesium alloy sheet to investigate the effect of the pulse current on the formability of the ZK60 magnesium alloy during the drawing process. The effects of thermal deep drawing and the thermoelectric coupling on the forming of drawn parts were studied, and the change laws of the thinning rate and hardness were obtained. The results showed that the use of pulse current improved the formability of the ZK60 magnesium alloy and increased the ultimate depth of drawing. The hardness value of the drawn part showed an overall increasing trend, followed by thermoelectric coupling deep drawing, which was signi cantly higher than the sheet after annealing without deep drawing. The deepdrawn parts had varied grain sizes in different places, and dynamic recrystallization occurred to varying degrees in each region. Furthermore, the degree of dynamic recrystallization in the punch llet and cylinder wall was signi cantly higher than in other areas.