Young’s modulus evolution and texture-based elastic–inelastic strain partitioning during large uniaxial deformations of monoclinic nickel–titanium Original Research Article

The authors draw upon recent first-principles calculations of monoclinic NiTi elastic constants to develop a combined numerical–empirical, texture-based approach for calculating the Young’s modulus of polycrystalline, monoclinic nickel–titanium specimens. These calculations are carried out for load direction inverse pole figures measured in situ via neutron diffraction during tension–compression deformations to ∼18% true strain, as well as unloading events. As demonstrated by application to this empirical data set, the texture-based approach results in the ability to quantify the evolution of Young’s modulus and to micromechanically partition elastic and inelastic macroscopic strains for the entirety of non-linear and asymmetric uniaxial deformations, a result that had not been achieved previously for a monoclinic material.