Effect of Ni and Mn additions on the damping characteristics of Cu-Al-Fe based high temperature shape memory alloys

Shape Memory Alloys (SMAs) are smart materials that involve a transition from the martensitic phase to the austenitic phase when induced by a change in temperature or stress. SMAs have been proven to possess damping properties, which is caused by the internal friction that occurs in the martensitic phase. This work focuses on exploring the damping properties of some copper-based ternary and quaternary SMAs using Dynamic Mechanical Analysis (DMA) by calculating internal friction. The results show that the peak value of damping lies near to the martensitic start temperature of the respective alloys. The addition of quaternary elements (Ni and Mn) to the existing ternary alloy decreases the transformation temperatures, thereby decreasing the temperature at which the peak damping value occurs. The Ni-Ti alloy attains its peak value of damping at temperatures lower than the temperatures at which peak value is attained for these alloys. Therefore, the results prove that the alloys developed are promising materials for damping applications which can be used over a wide range of temperatures.