Novel elastic deformation mechanism in multifunctional Ti-Nb alloy

In-situ high-energy X-ray diffraction was used to reveal a novel elastic deformation mechanism of the polycrystalline Ti-24Nb-4Zr-8Sn alloy under uniaxial compression. These experiments of polycrystal provide direct evidence on anomalous change in full widths at half maximum for {110}β peak during elastic deformation, i.e. peak broadening during unloading and peak narrowing upon loading, which is attributed to the formation of stress-induced irreversible ω phase as clearly demonstrated in single crystal during compression. Difference in modulus between ω and β phases induces different change in lattice strain causing the broadening and narrowing of diffraction peak near {110}β where actually contains {112̅0}ω under different applied stress. This study offers new perspectives to investigate intrinsic mechanism on specific phase transformation during elastic deformation.