Influence of Cobalt Content on the Fatigue Strength of WC-Co Hardmetals

The behavior of hardmetals under cyclic loads is investigated. Unnotched specimens were employed to obtain practical information regarding fatigue in hardmetals. All the tested hardmetals exhibit an increase in the number of cycles until failure with a decrease in the maximum stress, i.e., the hardmetals exhibit a high fatigue sensitivity. The fatigue strength increases with the cobalt content. Although distinct fatigue limits, as observed in metals, cannot be observed, the calculated fatigue limit stress at $10^7$ cycles is found to be approximately 70% of the flexural strength, and the stress value exhibits a linear relationship with the flexural stress.