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Cemented carbides are one of the most successful examples of effective implementation of multiphase composites for structural applications due to the strongly different properties of their two constituents: hard ceramic particles embedded in a metallic binder. Hard metals exhibit an excellent combination of toughness, strength, and toughness together with a unique resistance to wear and abrasion. As a result, they are prime candidates for tools used in the manufacturing industry, as well as for structural and wear-resistant components in a variety of other industrial sectors. Therefore, the use of cemented carbides at high temperature is a common and critical scenario.

In order to improve the performance of these materials in high-temperature environments, understanding the deformation mechanisms that occur at the nanometric scale is essential. In this study, nanoindentation and advanced microscopy techniques have been combined to perform in-situ measurements of mechanical properties under temperatures up to 600ºC. The main objective is, therefore, to identify the deformation mechanisms and micromechanical response of cemented carbides at room temperature and compare them to those observed at high temperature, with the ultimate goal of optimizing the materials design and application in extreme conditions.

To achieve this, micropillar compression tests were conducted. This technique is particularly suitable for studying deformation mechanisms in cemented carbides, as it allows the activation and observation of different mechanisms under controlled conditions. The uniaxial loading mode and limited interaction volume in micropillar compression tests reduce constraining effects and enable a more accurate analysis of plastic deformation fields, providing a controlled environment for studying the micromechanics of these materials.

Additionally, this approach minimizes artifacts, such as those induced by sample size or boundary conditions, which can complicate results in bulk testing.

Focused Ion Beam (FIB) milling was used not only to manufacture the micropillars, but to perform a post-deformation characterization by the obtaining of topographies. The combination of FIB milling and post-deformation characterization enables the detailed observation of localized deformation, crack initiation, and phase interactions, offering critical insights into the mechanical and thermal behavior of these multiphase composites.