Influence of microstructural parameters on the tribological behavior of multicomponent ferrous alloys
The aim of this work is to evaluate the effect of microstructural parameters (eutectic carbidesand matrix hardness) of multi-component ferrous alloys on tribological behavior in slidingwear and micro-abrasive wear. The samples were two series of alloys with variablevanadium (V serie) and molybdenum (M serie) contents and fixed amounts of otherelements. Each series includes an alloy free of carbides (matrix alloy) and alloys containingcarbides (carbide rich alloys). Heat treatments of quenching and tempering were performedto obtain three different levels of metallic matrix hardness. The wear configuration was ballon plane reciprocating sliding tests. Load, speed and temperature were fixed. The apparentfriction coeficient and wear rate were measured. Microabrasion wear test used free ballcrateringwith silica fine abrasives. The wear mechanisms of the types of tests werecharacterized by SEM and energy-dispersive X-ray (EDX). Friction was almost invariablewith volumetric fraction of carbides and nominal matrix hardness. Increasing matrix hardnessin alloys of V and M series was improved their wear resistance. The influence of carbideamount in wear rate was small effect in M serie alloys. In harder of the V series alloys thepresence of carbides protected the 650 HV matrix. However the increase of the amount ofcarbides did not altere the wear rate. The following wear mechanisms occured differentintensities on several alloys: pull-out of carbides, abrasion, and formation and break-down oftribochemical layers. In microabrasion, the relationship between microstructural parametersand abrasive wear coefficient was complex and not clear. The removal of matrix material dueto abrasion with fine silica particles decreased the mechanical supporting of the carbides,which caused intense fracture and their pull-out.
Advisor:Sinésio Domingues Franco; Jose Daniel Biasoli de Mello; Amilton Sinatora; Henara Lillian Costa; Cherlio Scandian; Mário Boccalini Júnior
School:Universidade Federal de Uberlândia
Source Type:Master's Thesis
Multi component ferrous alloys
Date of Publication:02/16/2007