Effect of Homogenization on Microstructure and Mechanical Properties of Al–Mg–Mn–Er Alloy

Abstract

As a traditional nonage‐hardenable aluminum alloy, 5XXX aluminum alloy has a limited dispersion‐strengthening effect since it is challenging to obtain high‐density and fine‐sized dispersoids by a conventional homogenization treatment process. In this work, three different homogenization treatments, single‐stage homogenization, slope heating homogenization, and double‐stage homogenization are used in a new type Al–Mg–Mn–Er alloy to exploit the dispersion strengthening. The precipitation behavior of submicron‐sized Mn‐containing dispersoids and nanosized Al3Er precipitates is investigated. In single‐stage homogenization, the nucleation of the Mn‐containing dispersoid is completed within a span of 2 h at 460 °C, accompanied by noticeable coarsening and the Al3Er precipitate tended to nucleate at dislocation sites and form a chain‐like structure. In slope heating and double‐stage homogenization, during the initial phase of heat treatment, lower temperatures facilitate the nucleation of dispersoids. This leads to the uniform precipitation of Mn‐containing dispersoids within the grain interior and improves the chain distribution of the Al3Er precipitates. The double‐stage homogenization generates the finest dispersoids. The alloy reaches maximum strength in the double‐stage homogenization, and the yield strength is 177 MPa, representing a 22% increase compared to the single‐stage homogenization.