Publication de 4 numéros par an
ISSN Imprimer: 2572-4258
ISSN En ligne: 2572-4266
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INVESTIGATING THE OPPORTUNITIES FOR DEFINING THE FATIGUE CHARACTERISTICS OF TOOLS WITH A NANOLAYER COATING DURING CUTTING
RÉSUMÉ
The efficiency of contemporary machine-building manufacture is closely related to ensuring the
quality in conditions of intensification and high-level automation of technological processes. The use of numerically controlled machines, automated machine complexes, and flexible production systems increased the process output efficiency significantly due to concentration of operations in the same equipment. However, unstable and, sometimes, low operational characteristics of the cutting tools remain a factor restraining further increase of mechanical processing efficiency. One of the most promising ways to increase tool durability by protecting the contact surfaces
(solid solutions and carbides) is the application of the cutting blades with a thin wear-resistant coating deposited layer by layer using ion-plasma methods. In such case, the thickness of the coating deposited in one run by the spray unit makes 20-200 nm. This work investigates hard alloys with such nanolayer nitride and oxide coating.
Such blades with wear-resistant coating should meet strict requirements in the process of their manufacture and operation. One of the conditions for successful application of the blades is a high degree of adhesion between the coating and the substrate. In identical coating conditions, the degree of adhesion is defined by the structural defects on the coating-substrate interface and the residual stress. The residual stress may not only reduce the adhesion, but deteriorate the coating properties, i.e., generate microcracks resulting in the coating chipping and fracture. Thusly, the operation efficiency of tools equipped with blades with wear-resistant coating depends not only on the wear resistance of the coating, but also on the coating-substrate characteristics and the effective stress.
Currently, the cutting properties of blades with a coating are evaluated only by the resistance, whereas methods for determining the fatigue characteristics of the blades with a deposited coating are nonexistent. In this work, we propose such method by testing it on nanolayer coating based on titanium nitride and aluminum oxide. Also, we investigate the modifications in the structure of the processed and worn samples of hard alloy with a coating.