Corrosion effects on hertzian contact fatigue behavior of a WC-Co cemented carbide

Abstract

The effect of corrosion on the damage induced under cyclic contact loading for a medium-grained WC-6%wtCo hardmetal grade is investigated. Contact fatigue tests are conducted by means of Hertzian indentation techniques. Corrosion damage is introduced in a controlled way by previous immersion of specimens in a stirred acidic medium. Results reveal that corrosion significantly influences the contact fatigue behavior of the material under consideration, in terms of the emergence and evolution of specific failure events: partial/full ring, radial cracks, and grain pull-out, among others. As cycle number increases, damage in the uncorroded condition evolves from partial to full ring cracks. Meanwhile, in the corroded condition, damage evolution is dominated by the appearance of grain pull-out when the number of cycles reaches a certain value. These findings are rationalized on the basis of phase assemblage changes linked to corrosion which are then enhanced by the cyclic nature of the applied loads.