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 high-temperature alloys, discuss strategies for optimizing microstructures for elevated-temperature 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.

Residual stresses affect the performance and reliability of most manufactured goods and are prevalent in casting, welding, and additive manufacturing (AM, 3D printing). Residual stresses are associated with plastic strain gradients accrued due to transient thermal stress. Complex thermal conditions in AM produce similarly complex residual stress patterns. However, measuring real-time effects of processing on stress evolution is not possible with conventional techniques. Here we use operando neutron diffraction to characterize transient phase transformations and lattice strain evolution during AM of a low-temperature transformation steel. Combining diffraction, infrared and simulation data reveals that elastic and plastic strain distributions are controlled by motion of the face-centered cubic and body-centered cubic phase boundary. Our results provide a new pathway to design residual stress states and property distributions within additively manufactured components. These findings will enable control of residual stress distributions for advantages such as improved fatigue life or resistance to stress-corrosion cracking.