Towards high-temperature applications of aluminium alloys enabled by additive manufacturing

Abstract

Research on powder-based additive manufacturing of aluminium alloys is rapidly increasing, and recent breakthroughs in printing of defect-free parts promise substantial movement beyond traditional Al-Si-Mg) systems. One potential technological advantage of aluminium additive manufacturing, however, has received little attention: the design of alloys for use at T >~200°C, or~1/2 of the absolute melting temperature of aluminium. Besides offering lightweighting and improved energy efficiency through replacement of ferrous, titanium, and nickel-based alloys at 200-450°C, development of such alloys will reduce economic roadblocks for widespread implementation of aluminium additive manufacturing. We herein review the existing additive manufacturing literature for three categories of potential hightemperature alloys, discuss strategies for optimizing microstructures for elevatedtemperature performance, and highlight gaps in current research. Although extensive microstructural characterisation has been performed on these alloys, we conclude that evaluations of their high-temperature mechanical properties and corrosion responses are severely deficient.

Enabling Rapid X-ray CT Characterisation for Additive Manufacturing Using CAD models and Deep Learning-based Reconstruction

“…Despite that, a comparison between Al alloys available for conventional manufacturing routes and AM shows that less than 3% of the former have been qualified for commercial AM applications 41 due to various limitations that are highlighted in 44 . There are, however, some promising new Al alloy families under development with exciting new properties that are not only competitive with conventional alloys but can even outperform them, particularly for elevated temperature applications 45 .…”

Microstructural Variations in Laser Powder Bed Fused Al–15%Fe Alloy at Intermediate Temperatures

“…However, the L-PBF-manufactured Al-15%Fe alloy exhibits refined microstructures [20,21] containing numerous nanosized particles of the metastable Al 6 Fe phase [22]. Moreover, the L-PBF-manufactured Al-15%Fe alloy shows a high yield strength of about 400 MPa at 300 • C [23], which is higher than that of both the 8xxx alloy series [24,25] (Al-Fe-based alloys used in powder metallurgy) and the L-PBF-manufactured Al-based multi-element alloys [18,26]. The hardness of these specimens slightly decreases after long-term thermal exposure, suggesting that the high thermal stability of the nanosized metastable Al 6 Fe phase strengthens the L-PBF-manufactured Al-Fe alloys.…”

“…The potential application of L-PBF-manufactured Al alloys in radial impellers operating at intermediate temperatures above 200 • C (inside the vehicle turbochargers) has encouraged the development of new Al alloys with superior strength at both ambient and intermediate temperatures. To accommodate the demand for materials with high-temperature strength, a variety of heat-resistant Al alloys, such as Al-Cr, Al-Mn, Al-Ni, Al-Ni-Fe, and Al-Ce-Mn, have been proposed for fabrication by L-PBF [17][18][19].…”

A Review on Material Extrusion Additive Manufacturing of Metal and How It Compares with Metal Injection Moulding

“…This process has become increasingly popular for various material fabrications, such as ceramic, polymer and metal [2][3][4][5]. Many metal AM processes, such as powder bed fusion (PBF), direct energy deposition (DED) and materials extrusion (MEX) can successfully fabricate various metals, e.g., stainless steel [6][7][8][9], titanium alloys [10][11][12][13], nickel alloys [14][15][16][17][18], cobalt [19,20] and aluminium alloys [21][22][23][24][25]. AM can also provide a high degree of freedom, lightweight design with almost unlimited shape, complexity and a varied range of sizes depending on the printing process [26].…”