Microstructure, Damping Effect, Shape Recovery, and Nanoprecipitation of Hot and Cold Rolled Fe-30Mn-6Si-6Cr Shape Memory Alloy

Fe-based shape memory alloys (Fe-SMAs) have attracted significant interest in various industries due to their outstanding properties, such as superior shape recovery, cost-effectiveness, weldability and vibrational damping capabilities. The ability to achieve shape recovery at room temperature expands their potential for use in a wide range of temperature-sensitive environments, further highlighting their adaptability and applicability in industrial setting. In this study, a series of mechanical processes-such as melting, wire-cutting, machining, grinding, and both hot and cold rolling-were carried out to fabricate the Fe-SMA samples. A specific composition, Fe-29.4Mn-6.2Si-6.2Cr, labeled as the S7-type, was subjected to nanoprecipitation treatment and compared with unprecipitated Fe-Mn-Si-based samples. The results indicated that the nano-precipitated S7-type sample demonstrated an energy absorption effect and damping dissipation ratio of 1649 N m and 21.13%, respectively, in contrast to the unprecipitated St37 samples, which showed values of 429.704 N m and 8.35%. Furthermore, The S7 sample exhibited a damping ratio 2.53 times greater than that of structural steel and 1.34 times higher than that of the S6 sample. This improvement is attributed to nano-sized precipitates that act as sources for the propagation of partial dislocations under applied stress. In conclusion, this research highlights the significant potential and enhanced properties of Fe-SMAs.