Boundary additive effect on abrasive wear during single asperity plowing of a 3004 aluminum alloy

Aluminum forming processes such as rolling, extrusion, and ironing involve the transfer of large loads through a tooling/workpiece interface to plasti cally deform the workpiece to a desired shape. Sharp tool surface asperitie s can plow the workpiece and lend to elevated friction and temperatures in the interface with a subsequent increase in abrasive wear debris which in t urn degrades the surface aesthetics of the final product To minimize associ ated friction and wear levels in aluminum forming processes, a base oil wit h one or more boundary additives is used as a lubricant. At the present tim e, however, little is known about the mechanisms by which a given additive influences abrasive wear in an aluminum metal forming interface. In the pre sent work, a series of single asperity plowing experiments on a 3004-O alum inum alloy with selected lubricant components was conducted. Three additive s were separately investigated viz, stearic acid, butyl stearate, and laury l alcohol. The plowing motion of a pyramidal diamond indentor with a cuttin g edge oriented in the plowing direction (i.e., a sharp indentor) was contr olled with the piezo-electric transducers of an atomic force microscope. Th e experiments kelp to provide insight about the interplay between additive reaction with the surface and plowing mechanics. Further insight into this interplay and abrasive wear debris generation was sought, albeit qualitativ ely, through additional experiments involving a diamond indentor for which no one cutting edge was oriented in the plowing direction (i.e., a blunt in dentor). The tests allowed evaluation of the boundary lubricant mechanism a nd propensity for generating wear debris.