Effects of aging and thermal cycling on the microstructure and damping behaviors of a porous CuAlMn shape memory alloy

摘要

Effects of aging and thermal cycling on the microstructure and damping behaviors of a porous CuAlMn shape memory alloy (SMA) were studied. It was found that with increasing aging temperature the intensity of the internal friction peak initially increased, followed by a decrease in the reverse martensitic transformation. In addition, the peak position shifted from low temperature to high temperature. This phenomenon has been ascribed to the refinement of martensitic laths as well as the annihilation of the quenched-in vacancies. The process of thermal cycling was also found to influence the damping behaviors of porous CuAlMn SMA. For instance, the damping behaviors of the alloys at ambient temperatures were observed to gradually increase, when subjected to 10 thermal cycles. However, when the thermal cycles exceeded above 20, the damping capacity began to decrease due to the newly generated dislocations and the disappearance of the spear-shaped martensite phase.