Date of Award
Doctor of Philosophy
Materials Science and Engineering
David J. Keffer, Eric Lass, O. Marcelo Suárez
Pursuing advanced structural materials with enhanced performance, reduced weight, and lower costs is a constant endeavor in the aerospace and automotive industries. Conventional structural alloys, such as cast irons, carbon steels, and titanium alloys, have strength, weight, and cost limitations. Aluminum-based alloys, known for their lightweight and high strength, have gained popularity in these industries. This dissertation focuses on investigating microstructure and mechanical behavior of novel powder-extruded Al-Ce-Mg alloys as potential candidates for high-performance structural materials.
This research explores using powder extrusion, a well-established forging methodology in the steel industry, to produce Al-Ce-Mg alloys with improved properties and aims to understand the influence of process conditions on microstructure development, evaluate the different phases present in the alloy under various heat treatment conditions, and analyze their influence on mechanical behavior.
The proposed Al-Ce-Mg alloy offers several advantages, including thermodynamic stability at elevated temperatures and refined microstructure through rapid solidification. By studying the alloys' microstructure and mechanical properties, this research contributes to the development of advanced manufacturing methods with improved material properties.
The study showed that the powder-extruded Al-8Ce-10Mg wt. % alloy exhibits high ultimate tensile strength of 687 MPa, compared to conventional high-magnesium Al-5083 alloys series with the UTS of 270-385 MPa. After heat treatments, the alloy gains back elongation from 1 % to 9 % while retaining 79 % of the UTS, a high-strength material compared to conventional aluminum alloys. Insights gained from this research can potentially lead to the production of high-strength aluminum-based alloys that outperform conventional Al-based alloys, some irons, and titanium-based alloys, potentially impacting various manufacturing applications.
Vazquez, Mairym, "Investigation of Microstructure and Mechanical Behavior of Novel Powder-Extruded Al-Ce-Mg Alloys. " PhD diss., University of Tennessee, 2023.