DAMPING BEHAVIOR OF Fe-Ni-Mn TERNARY ALLOYS

Abstract Fe-Ni-Mn alloys show good damping characteristics when they have an appropriate combination of composition relating to the stacking fault energy. The absorption mechanism of vibration energy may be in a dislocation configuration accompanied by stacking faults that extends over two slip planes to be crossed each other. The configuration should be maintained on a balance between back and forth stresses developed on each plane, so that, if the matrix were subjected to any external stress, two partials surrounded a stacking fault must be constricted to a perfect'dislocation, then it cross slips and rc-dissociates on the other plane. This mechanism can act as a dash pot and absorbs vibration energy. Experiments showed that the alloys with 3 to 7 mass % Ni and 11 to 15 mass % Mn possessed the most excellent damping properties which were evaluated by logarithmic decrement δ.