MICROSTRUCTURE AND MECHANICAL AND TRIBOLOGICAL PROPERTIES OF A LUBRICANT COATING FOR INCREMENTAL FORMING OF A TI SHEET

Abstract

Due to galling with other materials, Ti and its alloys call for solid lubricants duringforming. Deforming Ti sheet becomes even more difficult when the forming process involves verylow contact area, such as in the novel process single point incremental forming (SPIF). Retaininglubricant at the tool/sheet interface while performing local deformation, as in SPIF, has alwaysbeen a challenge. One way to satisfy this challenge is to develop a porous surface coating on thesheet and fill its pores with lubricant particles. For SPIF, an electro-chemical deposition processcalled micro-arc oxidation (MAO) has shown promise to fabricate coatings of desired pore sizeand thickness to fulfill the said objective. In the present work, the characterization of an MAOcoating has been carried out to clarify its role during the incremental forming of pure Ti sheet. Theresults regarding hardness, bond strength, XRD microstructure and friction co-efficient of thecoating under various lubrication conditions are reported.