A direct evidence for lattice selective rotation of molybdenum alloys single crystals in tensile deformation

The Mo-Nb-W-Zr quaternary single crystals were prepared using the electron beam floating zone melting technique. Samples fractured under tension were sectioned along the axial direction. The results revealed an absence of the single crystal-to-polycrystal transition during the tensile process. However, there was a noticeable alteration in crystal orientation between regions near and far from the fracture site. Upon analyzing three distinct regions, it was observed that the axial crystal plane index gradually shifted from the original (-1–11) towards the direction of (-110), passing through (-2–21), (-3–31), and (-4–41). The fracture occurred precisely when the crystal plane twisted to this (-110) direction. This implies that {110} represents a lattice-selective rotation for molybdenum-based single crystal torsion when subjected to stretching along the <111> direction.