Design of an Innovative Oxide Dispersion Strengthened Al Alloy for Selective Laser Melting to Produce Lighter Components for the Railway Sector

Abstract

The railway industry can take advantage of additive manufacturing (AM) processes from several perspectives such as the production of spare parts on-demand or the use of lightweight structures for vibration and noise control. One of the key issues regarding the limitations of using these technologies is the scarcity of processable material types. Selective laser melting (SLM) is a metal AM process with industrial maturity where material development can open new prospects for the railway industry. In order to respond to such requirements, this study proposes a framework to study a new material from concept to the processability and finally to the preliminary mechanical characterization of alloy for SLM. The new material is an alloy based on AlSi7Mg reinforced by alumina nano-dispersoids. The powder feedstock was produced through VIGA (Vacuum Inert Gas Atomization) technology, while the mechanical alloying of the nano-dispersoids has been carried out through the ball-milling process. The obtained oxide dispersion strengthened (ODS) powder has been used to produce samples by SLM. These samples have been characterized in terms of density, chemistry, and hardness. The obtained results showed that samples, produced by SLM were characterized by >1% porosity. Compared to the reference Al alloy, an increase up to 20% in microhardness was achieved for ODS samples made by the SLM process. The results show promise especially in terms of mechanical properties, even if additional work is needed concerning both the powder production and the AM process.