Effects of Cold Rolling Deformation on Microstructure and Damping Capacity of a Fe-Mn-Cr-Co-Si Alloy

The microstructure evolution of Fe-19Mn-8Cr-1Co-0.2Si (wt.%) alloy and Fe- 19Mn (wt.%) alloy during cold rolling and its effect on the damping capacity of the two alloys were investigated. It was shown that the damping capacity of the two alloys was enhanced significantly owing to the deformation-induced epsilon-martensite and stacking faults. The Fe-19Mn-8Cr-1Co-0.2Si alloy exhibited an accelerated phase transformation from gamma-austenite to epsilon-martensite due to a higher content of retained gamma-austenite and larger grain sizes compared with the Fe-19Mn alloy, resulting in a higher maximal increment of damping capacity in this alloy caused by deformation. It was observed that no twinned epsilon-martensite was generated in the Fe-19Mn-8Cr-1Co-0.2Si alloy during cold rolling, resulting in a remarkable increase in the volume fraction of alpha'-martensite owing to no impediment to epsilon -> alpha' transformation, hence the deterioration of damping capacity was slow because the alpha'-martensite weakened the pinning effect of dislocations on damping sources. In addition, new damping sources were provided due to the occurance of gamma-austenite twinning in the Fe-19Mn-8Cr-1Co-0.2Si alloy.