title: Deformation-induced structural transition in body-centred cubic molybdenum.
abstract: Molybdenum is a refractory metal that is stable in a body-centred cubic structure at all temperatures before melting. Plastic deformation via structural transitions has never been reported for pure molybdenum, while transformation coupled with plasticity is well known for many alloys and ceramics. Here we demonstrate a structural transformation accompanied by shear deformation from an original <001>-oriented body-centred cubic structure to a <110>-oriented face-centred cubic lattice, captured at crack tips during the straining of molybdenum inside a transmission electron microscope at room temperature. The face-centred cubic domains then revert into <111>-oriented body-centred cubic domains, equivalent to a lattice rotation of 54.7°, and ~15.4% tensile strain is reached. The face-centred cubic structure appears to be a well-defined metastable state, as evidenced by scanning transmission electron microscopy and nanodiffraction, the Nishiyama-Wassermann and Kurdjumov-Sachs relationships between the face-centred cubic and body-centred cubic structures and molecular dynamics simulations. Our findings reveal a deformation mechanism for elemental metals under high-stress deformation conditions.
authors.affiliation: 1] Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China [2] Beijing National Center for Electron Microscopy, Tsinghua University, Beijing 100084, China.
authors.forename: S J
authors.initials: SJ
authors.lastname: Wang
authors.affiliation: Division of Titanium Alloys, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.affiliation: 1] Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China [2] Beijing National Center for Electron Microscopy, Tsinghua University, Beijing 100084, China.
authors.forename: K
authors.initials: K
authors.lastname: Du
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
authors.forename: W
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124, China.
authors.forename: M L
authors.initials: ML
authors.lastname: Sui
authors.affiliation: 1] Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA [2] Center for Electron Microscopy, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: S X
authors.initials: SX
authors.lastname: Mao
mesh_terms: D003460:Crystallization; D008422:Materials Testing / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D056004:Molecular Dynamics Simulation; D008982:Molybdenum / Q000737:chemistry*; D013314:Stress, Mechanical
chemical_list: D008982:Molybdenum