Effects of nitrogen on γ → ε martensitic transformation and damping capacity of Fe-16%Mn-X%N alloys

Since the discovery of the high strain amplitude-dependent damping capacity of Fe–Mn binary alloys with the γ → ε martensitic transformation [1–3], the effects of the third element on both damping prop-erty and strength have been investigated. Unfortunately, however, the trials to improve both damping property and strength by addition of the third element did not meet expectations [4–6]. Most third elements used in the studies, such as C, Si, Co, and Cr, decreased the start temperature of γ → ε martensitic transformation (Ms), the start temperature of its reverse transformation (As), the amount of ε martensite at room temperature, and the damping capacity, although they increased the hardness and strength. Stoltz and Vandersande reported that N decreases th