Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Résumé

The present work investigates the influence of adding Mo to an Al-Mn-Mg 3004 alloy on elevated-temperature properties as well as their thermal stability during long-term thermal holding at 350°C and 400°C. In as-cast and heat-treated conditions, both microhardness and yield strength increase with increasing Mo contents and reach peak values at 0.3 wt. % followed by a plateau. With an optimized Mo content (0.3 wt. %), the volume fraction of dispersoids is increased while the volume percentage of the dispersoid-free zone is greatly reduced compared to the base alloy free of Mo, resulting in the remarkable increases in elevated-temperature strength and creep resistance. The results of the long-term thermal holding show that compared with the rapid drop of elevated-temperature strength and creep resistance in the base alloy, the Al-Mn-Mg alloy with 0.3% Mo is thermally stable up to 350°C, exhibiting a slight decrease of stability at 400°C. The combination of high elevated-temperature properties and their excellent thermal stability at 350-400°C with Mo addition makes Al-Mn-Mg 3xxx alloys the promising candidates for elevated-temperature applications.