The thermal deformation behavior of a NiTi actuated aluminum metal matrix composite

The present work reports macroscopic thermal mechanical and in-situ neutron diffraction measurements from a 22.9 volume percent, 50.7 at% Ni-Ti fiber actuated 6082-T6 aluminum matrix composite and 6082-T6 homogeneous aluminum control material subjected to an initial room temperature 4% tensile elongation and unloading process followed by a subsequent room temperature to 120 degrees C unconstrained (free) heating process. During the unconstrained room temperature to 120 degrees C heating process, the composite exhibited a pronounced, nonlinear thermal contraction, while the homogeneous control exhibited the expected linear thermal expansion. The composite thermal compression was clearly the result of a powerful shape memory response in the NiTi fiber actuators.