Quench-induced contributions of high angle grain boundary and low angle grain boundary to exfoliation corrosion propagation in an AlZnMgCu alloy

Abstract

The exfoliation corrosion behavior of an AlZnMgCu alloy extruded plate subjected to different quenching rates has been investigated. With the decrease of quenching rate, the number of corroded low angle grain boundaries (LAGBs) gradually increases in addition to high angle grain boundaries (HAGBs), leading to rapid development of corrosion along the thickness direction. Consequently, the corrosion morphology changes from layered features to wavy features. The reason has been discussed based on the quench-induced change of precipitation features at HAGBs and LAGBs.

Keywords

• AlZnMgCu alloy
• Corrosion
• Microstructure
• Quenching rate