Effect of Stress on the Damping Capacity of Damaged Damping Alloy under Fatigue Stress

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

“…Figure 2 shows an SEM image of a specimen damaged by 175-MPa fatigue stress. Microstructural observations confirmed the formation of martensite phases by fatigue stress, causing surface reliefs with a specific orientation and partially intersecting with each other [ 1 , 4 ]. Besides, the martensite produced due to fatigue stress is the same as that resulting from heat treatment and plastic deformation.…”

“…As the fatigue stress increases, the damping capacity, which corresponds to logarithmic decrement, increases. This increase can be demonstrated by the experimental result that the volume fraction of ε martensite linearly increases as the fatigue strength increases [ 1 , 5 ]. It should be noted that ε martensite is more dominant in damping capacity than α’ martensite because the relationship between ε martensite and damping capacity is more linear (green pentagons) than that between α’ martensite and damping capacity.…”

“…As the fatigue stress increased, the area fraction of martensite slightly increased in the alloy damaged under 105 MPa fatigue stress. The area fraction of martensite remarkably increased in a case of 245 MPa since many of the austenite transformed to martensite by fatigue damage [ 1 ].…”

“…This result is inconsistent with the general trend, in which the tensile strength is inversely proportional to damping capacity [ 27 ]. The increase in tensile strength and decrease in elongation as the fatigue stress increases in these alloys are attributed to the increased volume fraction of α′-martensite, whereas the damping capacity increases due to the increased volume fraction of ε-martensite [ 1 , 2 ].…”

“…Among them, damping technology using high internal friction in materials has the highest effect on damping capacity and excellent machinability. Thus, Kang et al [ 1 , 2 , 3 , 4 , 5 ] reported that damping alloys concerning strength and damping capacity in Fe-Mn alloys [ 1 , 2 , 3 ] and stainless steels [ 4 , 5 ], revealing that those depend on the phase fraction.…”