Scandium Extraction and Use in Aluminum Alloys: Scandium Containing Aluminum Alloys - Power Transmission and Additive Manufacturing
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: Timothy Langan, Sunrise Energy Metals; Samuel Wagstaff, Oculatus Consulting; Phil Chataigneau, Ppk Group Australia / Pdu Inc. ; Efthymios Balomenos, Mytilineos S.A.; Thomas Dorin, Deakin University; M. Akbar Rhamdhani, Swinburne University of Technology; Dimitrios Filippou, Rio Tinto Iron & Titanium; Henk van der Laan, V.I.C. Van der Laan International Consultancy BV; Frank Palm, Airbus Defence and Space GmbH
Tuesday 2:30 PM
March 21, 2023
Room: 30D
Location: SDCC
Session Chair: Thomas Dorin, Deakin University
2:30 PM
Effect of Sc, Zr and Other REE on the 1XXX Conductive Aluminium Alloys Properties: Alexander Gradoboev1; Dmitry Ryabov1; Ruslan Aliev1; Viktor Mann1; Aleksandr Krokhin1; Roman Vakhromov1; Dror Shaked1; 1Lmti Llc (Uc Rusal)
The modern trend of transport is electric vehicles. This is due to the high environmental friendliness of electric vehicles and international regulations that regulate carbon footprint. Aluminum alloys known as good alternative to Copper for use in bus bars and wires. In order to replace Copper for the manufacture of bus bars for electric vehicles, aluminium alloys should have high electrical conductivity at the level of technical grades (1350) and at the same time have increased strength and thermal stability. The most promising method of improving strength properties is doping with small additives Sc, Zr and REM, which form fine dispersed precipitates, providing an increase in strength properties, significantly increasing recrystallization temperature and thermal stability. In the present paper, a study of the effect of additives of a small amount of Sc, Zr, and other REM on mechanical properties and electrical conductivity alloys of aluminum of 1XXX series carried out.
2:55 PM
Developing Al-Zr-Sc Alloys as High-temperature-resistant Conductors for Electric Overhead Powerline Applications: Quan Shao1; Emad Elgallad1; Alexandre Maltais2; X.-Grant Chen1; 1University of Quebec at Chicoutimi; 2Rio Tinto Aluminum
The effect of small Sc additions (within ~0.1 wt.%) to improve the mechanical properties and electrical conductivity of Al-Zr-Sc conductor wires with two thermo-mechanical processing routes was investigated. The thermal resistance properties of Sc-containing wires after thermal exposure at 310 oC and 400 oC were investigated according to the international standard IEC 62004. The results show that a simultaneous improvement of mechanical properties and electrical conductivity while maintaining outstanding thermal resistance was achieved by micro-alloying with Sc and by using an optimized thermo-mechanical processing route. This was attributed to the precipitation of a high number of Al3(Sc,Zr) nanoparticles. Optimal properties with various combinations of the ultimate tensile strength and electrical conductivity (188-200 MPa and 58-60% IACS) were obtained with conventional casting, rolling and wire drawing techniques to fulfill the particular requirements of different conductor grades. The newly developed conductor alloys provide a much-needed outstanding performance for electric overhead line applications.
3:20 PM
The Development of New Aluminum Alloys for the Laser Powder-bed Fusion Process: Nathan Smith1; Mostafa Yakout2; Mohamed Elbestawi1; Phil Chataigneau3; Peter Cashin3; 1McMaster University; 2University of Alberta; 3Imperial Mining Group Ltd.
The laser powder-bed fusion processing environment poses significant challenges for the expansion of materials available for usage as a result of the drastic cooling rates native to this manufacturing method. First incorporated in the casting manufacturing ecosystem, the incorporation of small amounts of grain-refining rare-earth metals, particularly scandium, into aluminum alloys provides an avenue to resist the detrimental effects imposed by extreme thermal gradients. Through the analysis of solidification behavior, complementary element pairings, and owing to the supersaturation potential in these manufacturing conditions, a material design strategy is outlined based upon experimental observations. Results show that an extensive processing window exists for the material studied, with many opportunities for further improvement of print results available.
3:45 PM
Sustainable Scandium Recovery Method from Metallic 3D Printing Powders: Bengi Yagmurlu1; Carsten Dittrich2; 1TU Clausthal; 2MEAB Chemie Technik GmbH
With the upcoming limitations on gasoline-based vehicles, especially in Europe under the Paris Accord, research on electrical/hydrogen powered vehicles and lightweight alloys for lower CO2 emission has peaked. Scandium (Sc) became one of the key elements for advanced Al-based lightweight alloys due to major improvements in physical properties. Due to extreme prices and rare primary sources, recovery of Sc from available end-of-life (EoL) products are clearly became the focus of research. Al-Sc containing 3D printing powders are one of the promising products to be utilized in the industry. To recover the critical metals from these EoL products or from the production wastes, hydrometallurgical processes are great alternatives due to possibility of elemental separation with low energy consumption. However, conventional leaching of electronegative metallic particles and alloys with a strong mineral acid can result in generation of H2 gas and an aggressive exothermic reaction. While such a leaching process can be made safe at laboratory scale there are significant challenges at commercial scale from a control and zero harm perspective. Hence, there is a need for greener and sustainable process with easier control, lower chemical use, energy and CO2 emission without any H2 gas evolution. Thus, an innovative leaching approach was applied with a metal salt solution with higher reduction potential to dissolve the metallic powders with cementation of the metal from the leaching solution. Then, the target was separated and purified from the impurities via refining operations. The flexibility of end product is another advantage since metal-carbonates, -sulfates, -oxides, -fluorides and -oxides could be produced via this processing route. The process is also scaled up and tested in a continuous mini-pilot scale.
4:10 PM Break
4:25 PM
New Scandium Containing Aluminium Welding Wires for Wire + Arc Additive Manufacturing: Thomas Dorin1; Lu Jiang1; Andrew Sales2; 1Deakin University; 2AML3D Ltd
This work explores new welding wire compositions tailored for the emerging technology of Wire + Arc Additive Manufacturing (WAAM). The 5183 alloy is a commonly used welding wire as it provides strength through the presence of a high content of Mg through solid solution strengthening mechanism. These alloys experience a number of shortcomings such as medium strength compared to age-hardenable alloys and are prone to sensitisation when used in marine environment. This work uses co-additions of Sc, Zr and other transition elements to a 5xxx-series alloy to provide additional strengthening through the formation of L12 Al3X particles. The precipitation kinetics during a tailored heat treatment will be discussed. The impact on mechanical properties is evaluated with hardness and tensile tests. Atom probe tomography and transmission electron microscopy are used to better explain the role of the different elements on the formation kinetics of Al3X.
4:50 PM
Comparative Study of Al-Mg-Ti(-Sc-Zr) Alloys Fabricated by Cold Metal Transfer and Electron Beam Additive Manufacturing: Jiangqi Zhu1; Xingchen Yan2; Tim Langan3; Jian-Feng Nie1; 1Monash University; 2Guangdong Academy of Science; 3Sunrise Energy Metals
In this work, Al-5Mg-0.1Ti and Al-5Mg-0.1Ti-0.2Sc-0.1Zr (wt.%) alloys fabricated by cold metal transfer (CMT) and electron beam additive manufacturing (EBAM) are investigated. The Sc and Zr addition improves the processability of Al-Mg-Ti alloys with EBAM by eliminating cracks in their as-deposited microstructure. Additionally, the Sc and Zr addition promotes columnar to equiaxed transition in the as-deposited Al-Mg-Ti alloys, exhibiting a fully equiaxed microstructure with grain sizes decreased by at least 70% compared to the unmodified alloy in both cases. Grain refinement in the as-deposited Al-Mg-Ti-Sc-Zr alloy samples is attributable to: the inoculation effect of primary Al3(Sc,Zr,Ti) phase, the grain growth restriction effect provided by solute elements, and Zener pinning effect of the solid-state precipitates of Al3Sc. Moreover, the Sc and Zr addition improves the hardness and yield strength of Al-Mg-Ti alloys in the as-deposited state, achieved by grain size strengthening and precipitate strengthening mechanisms.
5:15 PM
Dissolution and Development of Al3(Sc,Zr) Dispersoids in 5025 Structures Produced via Wire Arc Additive Manufacturing: Sonja Blickley1; Tori Nizzi1; Anna Palmcook1; Austin Schaub1; Timothy Langan2; Carson Williams3; Paul Sanders1; 1Michigan Technological University; 2Sunrise Energy Metals; 3Hobart Brothers, LLC
Aluminum alloys are of growing interest in fields requiring high specific strength structural materials and are a promising choice for additive manufacturing applications. Aluminum wire arc additive manufacturing (WAAM) as a method of production is also increasing in development and use, predominantly using available welding filler alloys (i.e. 5356, 5183, etc.) as feedstock. As a manufacturing method, there is an interest in pursuing new aluminum alloy development to produce strengths superior to currently available materials. Alloys of aluminum and scandium offer increased strength and grain refinement as well as post-processing heat treatability that makes them well suited as a feedstock for WAAM applications, however the complex thermomechanical history of wire production, as well as the thermal input during WAAM processing, has significant impact on the dissolution, precipitation, structure, and morphology of Al3Sc dispersoids. In this work, aluminum alloy 5025 (5356 + 0.3 wt%Sc & 0.15 wt% Zr) is used to produce WAAM structures, and the resulting material microstructure and properties are characterized. Transmission electron microscopy is used to study Sc and Zr dissolution, Al3X dispersoid morphology, and dispersoid chemistry in WAAM samples in both as-printed and post-print heat treated conditions. Suggestions are made for optimizing use of Al-Sc alloys in WAAM applications.
5:40 PM Panel Discussion