A Retrospective View of Wear Research and Some Emerging Challenges

Compared to the study of friction, wear research is a much younger endeavor. While there is historical evidence of attempts to create wear-resistant surfaces, like pounding stones into the soles of wooden sandals or attaching metal strips to wooden plowshares, there was little scientific study of wear before the mid-twentieth century when Ragnar Holm conducted his signal work on electrical contact materials [1]. Modern instruments to magnify and study surfaces, and the use of bench-scale apparatus enabled wear research to be brought into the laboratory. Developments in heat treating, coating processes, and cleaner metallurgical practices for steels drove the desire to better quantify and understand the bases for improvements in wear resistance. Trends in wear research are indicated by the subjects of papers from the International Conferences on Wear of Materials. Near-term challenges in wear research include reaching a better understanding of non-steady-state processes of surface damage, reconsidering the traditional definitions for wear modes, and designing, modeling, and testing components under combined wear modes. Challenges for longer-term wear research include improving first-principles materials design and material selection for wear minimization, wear life-prediction for multi-mode systems, integrated surface engineering, and virtual wear testing as a means to avoid high development costs and to cope with the daunting number of choices of materials, lubricants, and surface treatments for wear mitigation.