Combinatorial investigation of Al–Cu intermetallics using small-scale mechanical testing

Abstract

In the past two decades, small-scale mechanical testing has become ubiquitous for mechanical measurements, offering new opportunities to quantitatively probe the mechanical behavior of materials. In this study, we applied four different small-scale mechanical testing techniques – conventional and statistical nanoindentation and micropillar compression and splitting tests – to study the mechanical behavior of Al–Cu intermetallics using a diffusion couple. This allowed the determination of the hardness, elastic modulus, yield stress, plastic flow behavior, and the critical stress intensity for fracture for nearly all of the intermetallic phases. A novel statistical indentation phase map plot was introduced, allowing the easy visualization of phases within property space. Hardness and elastic modulus results were found to be in good agreement with more recent studies and DFT predictions, while fracture results suggest the single crystal forms of the intermetallics show superior toughness. This work demonstrates that using small-scale mechanical testing in a combinatorial manner allows the interrogation of intermetallics with large composition ranges in a high-throughput manner with high precision and efficiency.