Relationship between the Tensile Properties and Damping Capacity of Fe-22%Mn-12%Cr-4%Co-3%Ni-2%Si Alloys by Fatigue Stress

The relationship between the tensile properties and damping capacity of fatigue-damaged Fe-22%Mn-12%Cr-4%Co-3%Ni-2%Si alloy under various magnitudes of fatigue stress was investigated. Analytical results show that α′- and ε-martensite were formed due to fatigue stress. The formed α′- and ε-martensite followed a specific orientation and surface relief and intersected with each other. TEM observation and pattern analysis reveal that both α′- and ε-martensites formed on the austenite. As a result of X-ray diffraction, with an increase in fatigue stress, the volume fractions of α′- and ε-martensite were increased, and the increasing rate of the volume fraction of α′-martensite was higher than that of the ε-martensite. As the fatigue stress increased, the tensile strength and damping capacity increased, but the elongation decreased. Besides, as the strength increased and the elongation decreased, the damping capacity decreased. This result is inconsistent with the general tendency for metals but similar to that of alloys undergoing deformation-induced martensite transformation.