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Introduction  Michael Alexandre et al.1 nanocomposites are a multi-phase strong material which has one or more dimensions of less than or equal to hundred nanometers (nm), or structures having the same nano-scale structure in cyclic order after a certain distance between the one or dimensions that forms the material.In mechanical terms, nanocomposites contrast from customary composite materials because of the incredibly high surface to volume proportion of the strengthening stage or potentially its especially high angle proportion. The strengthening material can be comprised of particles, sheets or nanotubes. The zone of the interface between the strengthening and matrix phases are generally more than that of for customary composite materials.  Fatigue  Fatigue is the process of weakening of a material which occurs when a material is subjected to repeated cyclic loads.The stress value that causes this damage is generally less than that of yield strength. Fatigue is progressive and localized in nature.  Fatigue life It is the number cycles that a material can withstand before showing any crack or failure.There are three methods to find fatigue life of a material stress life,linear elastic fracture, the strain life method.   Wear  Wear is defined as undesirable removal or shifting of material from the surface of the metal from its mean position.The size of the particles removed or shifted varies from a few micrometers to millimeter range.It generally occurs when two surface are working in close proximity or are in contact which other(asperities deformation).In general the harder surface removes the material from the softer surface in considerable quantity.Wear generally occurs between contact surfaces like metals, nonmetals, solid particles or liquid droplets restrained in flowing gasses.       Factors affecting wear  Unidirectional Sliding Reciprocating motion among surfaces Rolling between surfaces Impact loads Temperature of the surfaces Type of contact ranging between single phase or multiphase.  Types of Wear  Adhesive wear  Adhesive wear or friction wear occurs when two surfaces rub against each other with sufficient fores to cause the removal of material from the softer(less wear-resistant surface).Adhesive wear consists of galling wear, scuffing wear , scoring wear.It causes problems such as cold welding,scuffing,pit formation,seizures.  Abrasive wear  Abrasive or sliding wear occurs when a harder surface slide over the relatively softer surface or rolls over each other under pressure.It is usually categorized by the kind of contact and the contact condition. The type of contact decides the method of wear. There are two methods of wear known as two-body and three-body abrasive wear. Two-body wear happens when the harder aspirates removes the material from the relatively softer surface.this generally occurs by plowing operation. Three-body wear happens when the grits are not obliged and are allowed to roll and slide between surfaces.It consists of galling, scuffing wear and scoring wear.It causes corrugation and grooves.  Fretting wear  Fretting wear occurs when two or more surface rub against each other in repeated cycles.It increases as temperature of the surface in contact increases.  Erosive wear  Erosive wear (erosion) occurs when particles of solid or liquid slide and roll at relatively high velocity against a solid surface.  Corrosion and oxidation wear  Corrosive wear is a type of chemical reaction that occurs between two worn materials and a corroding medium which can be either reactive chemical reagent or even air.  Wear in industry  Abrasive 50% Adhesive 15% Erosion 8% Fretting 8% Chemical 5%      

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