title: Surface folding in metals: a mechanism for delamination wear in sliding.
abstract: Using high-resolution,in situimaging of a hard, wedge-shaped model asperity sliding against a metal surface, we demonstrate a new mechanism for particle formation and delamination wear. Damage to the residual surface is caused by the occurrence of folds on the free surface of the prow-shaped region ahead of the wedge. This damage manifests itself as shallow crack-like features and surface tears, which are inclined at very acute angles to the surface. The transformation of folds into cracks, tears and particles is directly captured. Notably, a single sliding pass is sufficient to damage the surface, and subsequent passes result in the generation of platelet-like wear particles. Tracking the folding process at every stage from surface bumps to folds to cracks/tears/particles ensures that there is no ambiguity in capturing the mechanism of wear. Because fold formation and consequent delamination are quite general, our findings have broad applicability beyond wear itself, including implications for design of surface generation and conditioning processes.
authors.affiliation: Center for Materials Processing and Tribology , Purdue University , West Lafayette, IN 47907, USA.
authors.forename: Anirban
authors.initials: A
authors.lastname: Mahato
authors.affiliation: M4 Sciences LLC , West Lafayette, IN 47907, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Civil Engineering , Indian Institute of Science , Bangalore, Karnataka 560012, India.
authors.forename: Narayan K
authors.initials: NK
authors.lastname: Sundaram
authors.affiliation: Center for Materials Processing and Tribology , Purdue University , West Lafayette, IN 47907, USA.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Chandrasekar
keywords: folding; high-speed imaging; metals; particles; sliding; wear