実用金属材料の空気中フレッチング摩耗における臨界相対変位量について

抄録

Fretting wear experiments in air were carried out for a carbon steel, aluminum alloy, 60/40 brass, and stainless steels. The tangential force during the steady-state period of fretting and the average wear rate after a given number of fretting cycles were measured at various levels of contact load P and peak-to-peak amplitude S of relative displacement. As a result, the existence of a critical amplitude S_cw of relative displacement was found for each material examined. Wear was very small below S_cw and rapidly increased with S above S_cw. The value of S_cw/P strongly correlated with the strain of the materials corresponding to their fatigue strength.
A change in wear mode with an increase in S is proposed as follows: in the region of elastic-adhesion contact at very small S wear debris is hardly produced because the contacting asperities are subjected to repeated stresses lower than the fatigue strength σ_w. In the mixed region of elastic-adhesion and microslip contact only the asperities in the microslip portion are subjected to repeated stresses higher than σ_w resulting in a small quantity of wear debris. Since in the macroslip region above S_cw repeated stresses higher than σ_w act on the asperities over the whole contact area, much wear debris is generated by fatigue wear and shear fracture due to adhesion.