Origin of strain softening in a nanograined Al alloy. (15th March 2023)

• Record Type: Journal Article
• Authors: Wu, Shangshu; Luo, Ting; Kou, Zongde; Tang, Song; Yan, Mengyang; Wang, Junjie; Fu, Shu; Ying, Huiqiang; Liu, Sinan; Wilde, Gerhard; Lai, Qingquan; Lan, Si; Feng, Tao
• Is Part Of: Scripta materialia. Number 226(2023)
• Publication Date: 2023-03-15
• Subjects: Al-Li alloys -- Grain boundary segregation -- Strain softening -- Dislocation density -- Deformation twins; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2022.115235
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: One-step and multi-step nanoindentation experiments were conducted to investigate the mechanical response of an Al-Mg-Li alloy. Opposite to the strain hardening effect observed in the coarse-grained (CG) alloy, the nanograined (NG) alloy exhibits strain softening. Compared with multi-step nanoindentation experiments, the ultralow dislocation density and the grain boundary (GB) segregation promote a higher stress level during one-step nanoindentation experiments. Residual perfect dislocations induced by a previous loading and unloading during multi-step nanoindentation experiments lower the stress required for further plastic deformation. In addition, the storage of partial dislocations also serves to render plastic flow to commence at lower stresses. This work provides new insights for the fabrication and property optimization of NG alloys. Graphical abstract: Image, graphical abstract