In milling, hard coatings often fail through cracking, delamination, and spallation caused by repeated impacts, rather than through uniform wear. Microtextures are commonly used to reduce friction and manage debris. They may also improve geometric anchoring and help maintain the integrity of the coating and substrate under repeated impacts. This exploratory study examines how substrate microtexture affects the cyclic impact damage response of AlCrSiTiN coatings. It also identifies texture design trends associated with reduced damage. YG8 cemented carbide discs were patterned with circular pit, V-shaped, or grooved textures at different areal coverages. All specimens were then coated under identical conditions. Constant-amplitude normal impact tests were performed. Damage evolution was evaluated using crater morphology, SEM/EDS analysis, and image segmentation of the damaged regions. Within the investigated design space, microtexturing reduced damage accumulation, limited crack propagation, and delayed coating delamination and spallation. Circular pit textures showed the lowest substrate exposure indicated by W. An areal coverage of approximately 13% was associated with the lowest overall damage among the tested conditions. At a fixed test duration, higher impact frequencies accelerated degradation because they increased the accumulated number of impact cycles. Textured surfaces reduced this frequency sensitivity, probably by redistributing local stress and retaining or compacting debris within the texture features. Each condition was tested only once, and coating thickness, residual stress, and adhesion strength were not independently characterized. The results should therefore be interpreted as exploratory evidence of trends rather than statistically validated rankings of damage resistance. Even with these limitations, this study provides a useful basis for texture design in hard-coated tools used under service conditions dominated by cyclic impact.
Liu et al. (Fri,) studied this question.