Observations on the Early Stages of Corrosion on AA2099-T83

A Matthew Glenn; Anthony E Hughes; Colin M MacRae; Nicholas C Wilson; Aaron Torpy; Xiaorong Zhou

doi:10.1017/S1431927620001634

Observations on the Early Stages of Corrosion on AA2099-T83

Microsc Microanal. 2020 Aug;26(4):821-836. doi: 10.1017/S1431927620001634.

Authors

A Matthew Glenn¹, Anthony E Hughes^{1

2}, Colin M MacRae¹, Nicholas C Wilson¹, Aaron Torpy¹, Xiaorong Zhou³

Affiliations

¹ CSIRO, Mineral Resources, Bayview Ave, Clayton, 3169 VIC, Australia.
² Institute of Frontier Materials, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia.
³ Corrosion and Protection Centre, School of Materials, The University of Manchester, ManchesterM13 9PL, UK.

PMID: 32513338
DOI: 10.1017/S1431927620001634

Abstract

An Al–Cu–Li aerospace alloy has been investigated to determine the order in which corrosion at different types of sites occurs in AA2099-T83. Specifically, the sequence of galvanic attack on intermetallic (IM) particles and other sites of AA2099-T83 was determined as a function of time, in 0.1 M NaCl, through the use of scanning electron microscopy and electron backscatter diffraction characterization techniques. The earliest attack occurred at isolated grains and grain boundaries and on Li-containing dispersoids. Similarly, some constituent IM particles showed evidence of trenching in the surrounding alloy matrix. These IM particles included Al7Cu2Fe and another group of unidentified particles which displayed complete trenching within the first 10 min of exposure. Al13(Fe, Mn)4 were next most active followed by Al37Fe12Cu2 with Al6(Fe,Mn) and large TiB2 particles being the least active.

Keywords: AA2099-T83; EBSD; corrosion; electron microprobe.