Internal friction of a new ingredient heterogeneous shape memory composite

摘要

The present work is aimed at the development of a new kind of ingredient heterogeneous shape memory composites, based on explosive welding, specifically designed to exhibit high damping in the wider temperature window. The DSC result shows that the synthesized shape memory composite still possesses the perfect shape memory effect, and the martensitic transformation temperature region has been broadened obviously. The micrograph shows that a straight interface is obtained after the hot rolling without any observable metallurgical defects. The damping properties have been characterized by mechanical spectroscopy as a function of temperature between -120 and 130°C, test frequency between 0.5 and 1.5 Hz, and strain amplitude at 5×10~(-5). The internal friction results show that there appear two damping peaks during the reverse martensitic transformation region and the height of damping peaks increase with the test frequency decreasing. Moreover, the abnormal behavior of the relaxation damping peak occurs during the measurement of the composite at the low temperature range, which the height of relaxation damping peak increases with the test frequency increasing. This result of our work disagrees with the rule of relaxation peak vs. test frequency which has been proposed through investigating shape memory alloy in published papers.