Article ID Journal Published Year Pages File Type
1472277 Corrosion Science 2006 18 Pages PDF
Abstract

Effect of heat treatments (namely T6, T73, RRA, OP1 and OP2) on the tensile strength (TS) and stress corrosion cracking (SCC) resistance of aluminum alloy 7050 in 3.5% NaCl solution at pH 12 has been investigated using constant extension rate tester (CERT). T6 increases the TS but decreases the SCC-resistance. To the opposite, T73 (i.e., T6 + 160 °C/30 h) increases the SCC-resistance but decreases the TS. Retrogression and re-aging (RRA, i.e., T6 + 200 °C/10 min + water quench + 120 °C/24 h) increases both TS and SCC-resistance but this treatment confines only to thin and small specimens. Step-quench aging (SQA, i.e., 470 °C/1 h + step-quench to 200 °C/1 min + water quench/or air cooling + natural aging at room temperature/1 week + 120 °C/24 h) provides a relatively practical treatment to enhance both the TS and SCC-resistance even the specimen either having quenched in water (OP1) or cooled in the air (OP2) in the process. Through electrochemical testing and micro-structural examination, we found that both the TS and SCC-resistance of AA7050 is governed by the microstructures that depend on heat treatments.

Related Topics
Physical Sciences and Engineering Materials Science Ceramics and Composites
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