Wear and Failure Mechanisms

The wear and subsequent failure of a cutting tool is a complex mechanism that usually involves a number of physical and chemical phenomena. Temperatures at the tool/workpiece interface (cutting edge) may reach up to 1200°C in a very short period of time. This creates a pronounced thermal shock and promotes oxidation of the tool surface and the diffusion of metallic constituents of the tool into the chip with a resulting loss of tool strength. 

Other wear mechanisms are flank wear and crater wear which occur mostly with cemented-carbide tools. Flank wear refers to the depression that is formed below the cutting edge on the side of the tool caused by the abrasive wear of the cemented carbide. TiC is particularly effective in reducing it. Crater wear occurs in the form of small depressions on the rake face behind the point of contact of the tool with the workpiece. Diffusion of the cobalt binder into the cutting chip usually occurs with crater wear. TiN is effective in reducing both diffusion and crater wear.PI 

Both CVD and PVD are used extensively in the production of coatings for cutting-tool applications. The PVD processes include mag- 

The selection of a coating process is much a function of the type of substrate to be coated as shown in the following section. 

Type of adhesion diffusion ion etching metallic bond 

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Handbook of Chemical Vapor Deposition 2.2 Wear and Failure Mechanisms... 

When modeling the fiber/matrix micro-structure, in order to study wear and failure mechanisms in real fiber-reinforced composites, an FE macro/micro contact model (introducing the displacement coupling technique) is much more suitable than using an equivalent macro-model. As a result, the calculated contact, stress, and strain results are significantly closer to the real conditions. 

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