Segregation of solute elements at grain boundaries in an ultrafine grained Al-Zn-Mg-Cu alloy

Gang Sha; Lan Yao; Xiaozhou Liao; Simon P Ringer; Zhi Chao Duan; Terence G Langdon

doi:10.1016/j.ultramic.2010.11.013

Segregation of solute elements at grain boundaries in an ultrafine grained Al-Zn-Mg-Cu alloy

Ultramicroscopy. 2011 May;111(6):500-5. doi: 10.1016/j.ultramic.2010.11.013. Epub 2010 Nov 19.

Authors

Gang Sha¹, Lan Yao, Xiaozhou Liao, Simon P Ringer, Zhi Chao Duan, Terence G Langdon

Affiliation

¹ Australian Centre for Microscopy & Microanalysis, The University of Sydney, NSW 2006, Australia. g.sha@usyd.edu.au, gang.sha@sydney.edu.au

PMID: 21159437
DOI: 10.1016/j.ultramic.2010.11.013

Abstract

The solute segregation at grain boundaries (GBs) of an ultrafine grained (UFG) Al-Zn-Mg-Cu alloy processed by equal-channel angular pressing (ECAP) at 200 °C was characterised using three-dimensional atom probe. Mg and Cu segregate strongly to the grain boundaries. In contrast, Zn does not always show clear segregation and may even show depletion near the grain boundaries. Trace element Si selectively segregates at some GBs. An increase in the number of ECAP passes leads to a decrease in the grain size but an increase in solute segregation at the boundaries. The significant segregation of alloying elements at the boundaries of ultrafine-grained alloys implies that less solutes will be available in the matrix for precipitation with a decrease in the average grain size.