Influence of in-plane stress state on sliding contact fatigue damage of metallic surfaces

Current study investigates stress-dependent fatigue wear mechanism of pure copper surfaces in ambient environment. The stressed copper surface by a unique bending fixture is subjected to sliding motion of the atomic force microscope probe. Wear volumes are determined at different contact loads with variable bending stresses. Experimental results indicate that the surface damage is accelerated under compressive stresses and suppressed under tensile stresses with the similar contact pressures. A numerical model of fatigue stress intensity factor at the subsurface crack is proposed to explain the stress-dependent fatigue damage mechanism. The numerical study agreed compressive surface stress accelerates fatigue wear. Consequently, experimental and numerical studies on dry sliding contact damage concludes a significant dependence of the surface stress on ductile metal surface.