In-situ observation of influence of metal types on wear process in dry conditions

We conduct in-situ observations of the wear process of metals in dry conditions. To this end, we constructed an experiment to observe the wear process of a point contact area, created between a rotating sapphire disc and a metal pin. The experimental setup included a microscope and a camera with visible-light and near-infrared detectors. Several steels, including stainless steel, and copper alloys were tested as pin materials. The wear comprised plastic flow, formation of transfer layers from the metal pin onto the sapphire disc, and expansion of the contact area. The influences of metal compositions and base metals on the wear behaviour were discussed. [Display omitted] •The wear process between a sapphire disc and a metal pin were in situ observed.•Several steels and copper alloys were employed as materials of the pin.•Intermittent plastic flow and the formation of transfer layers were observed.•The wear behaviour depended on compositions of the metals.