Precipitates in long term aging A15083 alloy

Abstract

A1 5083 alloy aged at 343 K (70 °C) for 3-30 months was evaluated by high resolution transmission electron microscopy (HRTEM) results show that both thickness and continuity of β phase formed at grain boundaries increase with time. GP zones are observed in A1 5083 aged at 343 K for 3 months for the first time. TEM results reveal that GP zones can form homogeneously with the help of vacancies as well as heterogeneously at dislocations near grain boundaries, and the mechanism are explained in detail. Mg2Si precipitate was found to form at the grain boundary and energy-dispersive X-ray spectroscopy (EDS) results reveal that a Mg, Si (atomic ratio 1:1) rich phase nucleates at the interface of Mg2Si-matrix. β phase(Al 3Mg2, hexagonal) is observed to form at grain boundaries of A1 5083 alloy aged at 343 K for 30 months. β phase was found at the grain boundary of A1 5083 aged at 343 K for 12 months using EDS. Copyright © 2014 by The Minerals, Metals & Materials Society.