EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

WC-base cemented carbides, also referred to as hardmetals, have been the subject of intensive research and technological applications for past few decades, especially for metal cutting, mining and earth drilling industries. Several of these applications also include exposure to chemically aggressive media, such as lubricants, chemical products, petrochemical and mine slurries, and seawater. Under these conditions, it has been shown that failure induced under applied load is accelerated, and corresponding service life may be significantly shortened. In this regard, several works have attempted to replicate – at the laboratory level – similar service-like conditions. Among them, the detrimental corrosion-related effects on tribological response and effective wear resistance of cemented carbides have aroused the greatest concern. However, investigations addressing similar information linking corrosion-induced damage and mechanical contact response are quite limited. It is the main objective of this work to evaluate such interactive effects on microstructurally different WC-base cemented carbides. The investigation combines the implementation of Hertzian indentation techniques and consideration of variable corrosion times. Corrosion effects on corresponding mechanical response and damage were assessed for three grades with metallic binders of different chemical nature. Results point out that corroded cemented carbides exhibit a lower load-bearing capability than pristine ones. Such detrimental influence is particularly evidenced in terms of contact damage: lower critical loads for the emergence of incipient cracks, and more severe evolution scenarios at the surface level. Considering these parameters as figures of merit for material selection, addition of Cr and Co-base is found to be an optimal option for applications involving corrosion and contact loads. Significant corrosion effects on contact response are also evidenced at the subsurface level, in terms of deformation/damage micromechanisms.