Preparation of NiTip/Al composites with controllable phase transformation and damping behavior by friction stir processing

The NiTip/1060Al composites were prepared using a pre-aging and friction stir method (FSP) to enhance the low-temperature damping performance of the aluminum alloy and accommodate various service temperatures. The bonding between NiTi particles and the 1060Al matrix is well established after FSP, and no new phases are formed in the composites. The phase-transformation peak temperature of NiTip/1060Al composites gradually shifts to lower temperatures with increased aging temperature of NiTi particles. At room temperature, the 550°C-NiTip/1060Al composite exhibits superior damping performance, with an internal friction value 144% higher than that of the FSP-1060Al alloy. However, at −91°C, the 650°C-NiTip/1060Al composite demonstrates better damping performance, with an internal friction value 158% higher than that of the FSP-1060Al alloy. The NiTip/1060Al composites exhibit the internal friction peak of NiTi phase-transformation in the temperature range from −91°C to 60°C. This characteristic results in significantly better damping performance compared to the FSP-1060Al alloy and other high-damping aluminum matrix composites.