Regional morphological difference and evolution of tread rubber and its formation mechanism under high-speed sliding friction

The tribological behaviors of tread rubber were gradually changed by the worn surface morphologies during friction. The high-speed sliding friction test was conducted by self-developed friction apparatus to investigate the tribological behaviors of the tread rubber. The fan-shaped rubber specimen was tangent to a grinding wheel to simulate the tread-road contact. A clear abrasion pattern can be observed on the rubber surface after sliding friction, which was further captured by the optical digital microscope and scanning electron microscopy for morphological analysis. The worn surface can be divided into three areas, which were mainly formed by the effects of stretching, abrasion, and compression, respectively. The morphological evolution of the worn surface was contributed by frictional force-promoted horizontal expansion and abrasion-promoted vertical expansion. The horizontal and vertical expansions were inhibited and accelerated by high friction speeds, which reduced friction coefficient and caused severe abrasion, respectively. Therefore, increases in specific mechanical properties and moderate acceleration processes were recommended for ideal tribological performance.