Developing new metallic alloys for Additive Manufacturing

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Canadian manufacturing accounts for 10% of GDP and nearly 10% of the labour force (Statistics Canada). Additive manufacturing (AM), or 3D printing, is a new manufacturing approach where three dimensional components are built layer by layer forming a complex 3D part. This manufacturing approach deviates significantly from traditional manufacturing. Typically, components are designed and cast followed by hot and cold working, heat treatment and machining. AM provides innovative new opportunities for re-designing components. AM is undergoing a dramatic rise expanding in 2017 by more than $2.15 billion and a 21% overall growth in the industry. New metallic alloys must be developed to meet the special needs for innovative designs of components hitherto thought impossible to make. Innovative designs include the use of truss lattices in AM components. This enables the use of powdered alloys with novel compositions not yet used for engineering applications. Aluminum-copper alloys (Al-Cu) is one example, where traditionally the copper content is limited to ~4.5wt% due to light-weighting goals and increased strength. With the advent of truss designs for AM, higher copper content alloys may be utilised while producing components with lighter densities than traditional monolithic materials and with a considerable increase in strength. It is proposed to begin this program by studying Al-Cu and Al-Ni of eutectic and near-eutectic compositions. Of initial interest is the process conditions under which eutectics form. Subsequently, the ability to spheroidize the intermetallic constituent of the eutectic by aging will be studied. The powders will then be used in AM equipment in collaboration with Prof Qureshi, Mech E UofA. This will stimulate new projects funded by industry and NSERC using these novel powders in making AM components. The eutectic microstructures will be quantitatively characterized using scanning electron microscopy, neutron scattering and 3D micro-tomography. The evolution of spherical intermetallics will be defined following Ho and Weatherly. The spacing between intermetallic particles and their size will be measured using quantitative image analysis and machine learning techniques. Finally, these measurements will be related to Vickers micro hardness measurements to be made on aged samples. Four graduate students will be trained over the duration of 5 years. Two will tackle Al-Cu and two Al-Ni. One set of two students will address the rapid solidification aspects of the project while the other two will address the ageing processing of the powders. This will provide all 4 students training in the conduct of high temperature experiments, characterisation methods, 3D microtomography, quantitative metallography as well as modelling of solidification paths of alloys and the relationship between solidification-developed microstructure and resulting properties. The effort described in this proposal initiates a new thrust in our research.