Damping behavior and mechanical properties of novel Acrylic/TiNi composites

Metal-matrix composites with high damping capacity and excellent energy absorption properties have extensive application requirements. Porous TiNi shape memory alloys with a three-dimensional connected structure were firstly prepared by powder metallurgy technology consisting of "uniform-mixing, compaction, dissolution and sintering" four stages. Then, the novel Acrylic/TiNi composites were manufactured in light of vacuum negative pressure infiltration technology. The damping properties were characterized by internal friction. It was found that Acrylic/TiNi composites exhibit a much higher damping capacity than that of corresponding TiNi porous materials, especially in around room temperature zone. It was rationalized that the great improvement of the damping capacity is originated from the intrinsic high-damping of Acrylic phase as well as induced massive interface damping between TiNi porous matrix and Acrylic phases. The quasi-static compressive mechanical measurement shows that Acrylic/TiNi composites can achieve energy absorption efficiency similar to that of TiNi porous alloy, the reason of which is confirmed to be associated with the longer and smoother compression plateau area of TiNi composites. In addition, the full penetration of the Acrylic reinforced phase greatly enhances the energy absorption capacity and yield strength of the composites. Deformation mechanism analysis of the TiNi composites indicates that the mutual compensation and coupling between porous matrix and Acrylic fillings during the compressive process can be considered to account for the improved energy absorption characteristics.