Improved shape memory composites combined with TiNi wire and shape memory epoxy

Highlight
• The stiffness decrease of shape memory epoxy at elevated temperature has been compensated by adding TiNi wires.
• The maximum recovery stress of composites is 4.04 MPa, which is almost 3 times of matrix.
• The rates of shape fixity and shape recovery of 1 vol% composite with 8% pre-strain are close to 100%.

In order to develop high functionality of shape memory materials, the shape memory composites combined with TiNi wire and shape memory epoxy were fabricated, and the mechanical and thermomechanical properties were studied. The results showed that TiNi wire can compensate for the stiffness decrease of SMPs at elevated temperature, and the strength of interface and strength of interface matrix were important to further increase elevated temperature mechanical properties. The recovery stress of composites could be adjusted by changing the pre-strain, and the maximum recovery stress was obtained at 8% which was TiNi wire maximum recoverable strain. The addition of 1 vol% TiNi wire could increase the maximum recovery stress from 1.36 MPa to 4.04 MPa, which was almost 3 times of the matrix and at the same time maintained the rates of shape fixity and shape recovery close to 100%.