title: Metallurgy. Origin of dramatic oxygen solute strengthening effect in titanium.
abstract: Structural alloys are often strengthened through the addition of solute atoms. However, given that solute atoms interact weakly with the elastic fields of screw dislocations, it has long been accepted that solution hardening is only marginally effective in materials with mobile screw dislocations. By using transmission electron microscopy and nanomechanical characterization, we report that the intense hardening effect of dilute oxygen solutes in pure α-Ti is due to the interaction between oxygen and the core of screw dislocations that mainly glide on prismatic planes. First-principles calculations reveal that distortion of the interstitial sites at the screw dislocation core creates a very strong but short-range repulsion for oxygen that is consistent with experimental observations. These results establish a highly effective mechanism for strengthening by interstitial solutes.
authors: Department of Materials Science and Engineering, University of California, Berkeley, CA, USA. National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
authors: Qian
authors: Q
authors: Yu
authors: Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
authors: Liang
authors: L
authors: Qi
authors: Nuclear Science and Engineering Directorate, Japan Atomic Energy, Tokai-mura, Ibaraki, Japan.
authors: Tomohito
authors: T
authors: Tsuru
authors: Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
authors: Rachel
authors: R
authors: Traylor
authors: Rolls Royce, Derby DE24 8BJ, UK.
authors: David
authors: D
authors: Rugg
authors: Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
authors: J W
authors: JW
authors: Morris
authors: Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
authors: Mark
authors: M
authors: Asta
authors: Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
authors: D C
authors: DC
authors: Chrzan
authors: Department of Materials Science and Engineering, University of California, Berkeley, CA, USA. National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. aminor@berkeley.edu.
authors: Andrew M
authors: AM
authors: Minor