Size-dependent of compression yield strength and deformation mechanism in titanium single-crystal nanopillars orientated [0001] and [112̄0]

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2014-10, Vol.615, p.22-28
• Main Authors: Ren, Junqiang, Sun, Qiaoyan, Xiao, Lin, Ding, Xiangdong, Sun, Jun
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects and impurities in crystals; microstructure; Deformation mechanisms; Dislocations; Elasticity, elastic constants; Exact sciences and technology; Linear defects: dislocations, disclinations; Materials science; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Methods of crystal growth; physics of crystal growth; Molecular dynamics; Molecular dynamics simulation; Nanostructure; Physics; Simulation; Single crystals; Size effect; Structure of solids and liquids; crystallography; Surface effect; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; Titanium; Vibration; Yield strength
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2014.07.065

Different size effects and deformation mechanisms are revealed in α-titanium (Ti) single crystal nanopillars orientated for [112̄0] and [0001] based on molecular dynamics simulations. The strength–size relationship changes from “smaller is stronger” to “smaller is much weaker” when the width of nanopillars reduces from 19nm to 3nm. The “smaller is much weaker” is attributed to that the surface effect caused by a thermal vibration of surface atoms leads to the initiation and growth of surface dislocations.