冶金学。钛中戏剧性的氧溶质强化效应的起源。

Metallurgy. Origin of dramatic oxygen solute strengthening effect in titanium.

机构信息

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.

Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.

出版信息

Science. 2015 Feb 6;347(6222):635-9. doi: 10.1126/science.1260485.

DOI:10.1126/science.1260485

PMID:25657243

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.

摘要

结构合金通常通过添加溶质原子来增强。然而，由于溶质原子与螺位错的弹性场相互作用较弱，长期以来人们一直认为，在具有可动螺位错的材料中，固溶强化的效果微不足道。通过使用透射电子显微镜和纳米力学表征，我们报告说，在纯α-Ti 中，稀氧气溶质的强烈硬化效应是由于氧与主要在棱柱面上滑移的螺位错核心之间的相互作用。第一性原理计算表明，位错核心的间隙位置的变形为氧创造了一个非常强但短程的排斥力，这与实验观察结果一致。这些结果为间隙溶质的强化建立了一种非常有效的机制。