A tale of two mechanisms: Strain-softening versus strain-hardening in single crystals under small stressed volumes. (1st January 2016)

• Record Type: Journal Article
• Authors: Bei, H.; Xia, Y.Z.; Barabash, R.I.; Gao, Y.F.
• Is Part Of: Scripta materialia. Volume 110(2016)
• Page Start: 48
• Page End: 52
• Publication Date: 2016-01-01
• Subjects: Nanoindentation pop-in -- Weakest link -- Strain hardening; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2015.07.043
• Languages: English
• ISSNs: 1359-6462

Abstract

Graphical abstract: Abstract: Pre-straining defect-free single crystals will introduce heterogeneous dislocation nucleation sources that reduce the measured strength from the theoretical value, while pre-straining bulk samples will lead to strain hardening. Their competition is investigated by nanoindentation pop-in tests on variously pre-strained Mo single crystals with several indenter radii (∼micrometer). Pre-straining primarily shifts deformation mechanism from homogeneous dislocation nucleation to a stochastic behavior, while strain hardening plays a secondary role, as summarized in a master plot of pop-in strength versus normalized indenter radius.