Structural parameters of 7020 alloy after heat treatment simulating the welding process

The study presents quantitative analysis of particle and grain size distrib utions in AI-Zn-Mg (7020) alloy subjected to a heat treatment simulating th e welding process. Microstructural analysis was done by the APHELION progra m. Some significant quantitative changes in the size and distribution of pa rticles as a function of the heat treatment temperature were observed, The changes were related to the process of growth, dissolution, and precipitati on of new, fine particles from the solid solution. The heat treatment was o bserved to have no effect on the grain size and on the size of the largest particles visible under an optical microscope. These phenomena, which influ ence the strength hardening and residual stress fields decide the propertie s of the welded joints. (C) 2001 Elsevier Science Inc. All rights reserved.