Alexey Anatolevich Vereschaka

Study of Properties of Nanostructured Multilayer Composite Coatings of Ti-TiN-(TiCrAl)N and Zr-ZrN-(ZrNbCrAl)N

The structures of surface layers of the tool material, adapted to the conditions of the thermomechanical loading during the cutting process, can be formed with the use of different processing methods, the most effective of which is to deposit functional coatings on working surfaces of the cutting tool. During the studies, two nanostructured multilayer composite coatings (NMCCs) were considered: Ti-TiN-(TiCrAl)N and Zr-ZrN-(ZrNbCrAl)N. Metallographic studies were conducted, and the phase compositions of the coatings were determined by X-ray crystal analysis. The efficiency of tools made of carbide T14K8 with developed coatings was determined by comparative evaluation of tool life of a tool without coating, a tool with standard coating (TiN), and a tool with elaborated coatings (Ti-TiN-(TiCrAl)N and Zr-ZrN-(ZrNbCrAl)N) in turning structural steel 45. These tests allow noting the increase in tool life of a tool with elaborated NMCCs by up to 4 times as compared with tool life of an uncoated tool and by up to 2 times as compared with tool life of standard coating TiN. Meanwhile, NMCC of Ti-TiN-(TiCrAl) showed lifetime about 10% longer than NMCC of Zr-ZrN-(ZrNbCrAl)N). The longer lifetime of NMCC of Ti-TiN-(TiCrAl) conforms to its better adhesion characteristics and thinner nanosublayers of its wear-resistant layer.

Improvement of Working Efficiency of Cutting Tools by Modifying its Surface Properties by Application of Wear-Resistant Complexes

The paper presents the results of the methodology for improving of cutting tools performance based on modifying the surface properties of the tool material in the formation of wear-resistant complexes, substantially modifying its properties. Argued and offers a three-component (for carbide tools) and four-component (for HSS tools) system for modifying the surface properties, improves the tool material. This paper describes a method and results of research to note the substantial increase of efficiency of HSS drills and milling and turning tools made of carbide in the processing of structural steel and hard-to-cut superalloy.

Development of Assisted Filtered Cathodic Vacuum Arc Deposition of Nano-Dispersed Multi-Layered Composite Coatings on Cutting Tools

This paper presents the results of development and application of processes for modification of various properties of working surfaces of cutting tools by condensing vapor and ion flows in assisting impulse or constant exposure to high-energy ions. The paper shows features of the technology and equipment for the formation of wear-resistant components, which modify the structure and properties of working surfaces of various edge cutting tool types in a wide range of temperatures, in order to improve tool life and reliability. Various properties of the modifying components were studied, and their ability to improve the operational efficiency of different types of carbide cutting tools for cutting various materials was shown.

Improving the Efficiency of the Cutting Tools Made of Mixed Ceramics by Applying Modifying Nanoscale Multilayered Coatings

The paper studies the influence of properties of a tool made of mixed ceramic by applying modifying with nanoscale multi-layered coatings on machinability of hardened tool steel XVG. The paper also examines the influence of cutting speed on wear resistance of mixed ceramic with nanoscale multilayered coatings. The mathematical models that found out the dependence of tool life of a ceramic tool with coating from cutting speed were developed.

Control of Structure and Properties of Nanostructured Multilayer Composite Coatings Applied to Cutting Tools as a Way to Improve Efficiency of Technological Cutting Operations

The study considers the challenge of improving the efficiency of dry finishing and semi-finishing turning of (P10-P20) steel with carbide tools with complex composition coatings by directed selection of the composition and properties of the coatings through the control of the parameters of the filtered cathodic vacuum-arc deposition (FCVAD). The conducted tests have confirmed the feasibility and effectiveness of the control of compositions, structures, and properties of complex composite coatings of Ti-TiN-TiAlN type by varying the parameters of the FCVAD process. In particular, it has been found out that the ratio of Ti/Al, which greatly affects the important properties of the coating (grain size, lattice parameter, microhardness, fracture toughness, etc.), can be changed at constant compositions of cathodes by varying such parameters of coating synthesis as titanium cathode arc current, nitrogen pressure, and substrate shear stress. It has been shown that Ti-TiN-TiAlN coating produced at different values of the parameters of synthesis significantly changes the cutting properties of carbide tool and thus allows optimizing the coating composition for a variety of machining conditions.The developed methods are also applicable for multi-component complex composite coatings.

Improving the Efficiency of the Cutting Tool Made of Ceramic when Machining Hardened Steel by Applying Nano-Dispersed Multi-Layered Coatings

The functional role of nano-dispersed multi-layered composite coatings (NMCC) deposited on the working surfaces of cutting inserts (CI) made of the layered high-strength ceramic (LHC) to equip the cutting tools when cutting hardened (high-strength) steels was investigated. It is shown that the variation in the composition, structure and properties of coatings allows controlling the contact processes at cutting, increasing the length of contact, reducing normal contact stresses and probability of micro- and macro-brittle failure of tool cutting edge. The mathematical models of cutting which establish dependences of flank wear land of the tool, the tangential component of cutting force, power of cutting and roughness of the machined surface from conditions of cutting of high-strengthen steels are developed. It is found out that the application of nano-dispersed ceramic multi-layered coatings on ceramic tool significantly increases its wear resistance and improves the quality of machining.

Nano-Scale Multi-Layered Coatings for Cutting Tools Generated Using Assisted Filtered Cathodic-Vacuum-Arc Deposition (AFCVAD)

The subject of this study were nano-nanoscale multilayer coatings formed using the process of filtered cathodic vacuum arc deposition in assisting high-energy ions of chromium. We used a special emitter (implantor) to generate chromium ions with high energy. Such key parameters of coatings as composition, structure, a thickness, hardness, adhesion in relation to a substrate obtained at various energy of chrome ions have been studied. It is establish the positive change of key properties of coating deposited on carbide inserts WC/CrC/Co, WC / (Co-Re), TiC/TaC/Co at assisted impact of ions Cr at ion acceleration voltage within the range of 10-40 kV. The results of measurement of parameters of coatings with use nanoindentometer are consistent with the X-ray analysis of the stresses in the coating (XSA study). The mechanisms of the effect of modified properties of coatings formed in assisting the filtered cathodic vacuum arc deposition on the properties of the carbide inserts in cutting structural steels and hard-to-cut nickel alloys have confirmed the high efficiency of the deposition process developed coatings and coating compositions.

Improvement of structure and quality of nanoscale multilayered composite coatings, deposited by filtered cathodic vacuum arc deposition method

This article studies the specific features of cathode vacuum arc deposition of coatings used in the production of cutting tools. The detailed analysis of the major drawbacks of arc-Physical Vapour Deposition (PVD) methods has contributed to the development of the processes of filtered cathodic vacuum arc deposition to form nanoscale multilayered composite coatings of increased efficiency. This is achieved through the formation of nanostructure, increase in strength of adhesion of coating to substrate up to 20%, and reduction of such dangerous coating surface defects as macro- and microdroplets up to 80%. This article presents the results of the studies of various properties of developed nanoscale multilayered composite coating. The certification tests of carbide tool equipped with cutting inserts with developed nanoscale multilayered composite coating compositions in longitudinal turning (continuous cutting) and end symmetric milling, and intermittent cutting of steel C45 and hard-to-cut nickel alloy of NiCr20TiAl showed advantages of tool with nanoscale multilayered composite coating as compared to the tool without coating. The lifetime of the carbide inserts with developed NMCC based on the system of Ti–TiN–(NbZrTiCr)N (filtered cathodic vacuum arc deposition) was increased up to 5–6 times in comparison with the control tools without coatings and up to 1.5–2.0 times in comparison with nanoscale multilayered composite coating based on the system of Ti–TiN–(NbZrTiCr)N (standard arc-PVD technology).

Study of Mechanism of Failure and Wear of Multi-Layered Composite Nano-Structured Coating Based on System Ti-TiN-(ZrNbTi)N Deposited on Carbide Substrates

The aim of this paper is to study physical and chemical properties of nanostructured multi-layered composite coating based on three-layered architecture of Ti-TiN-(ZrNbTi)N, deposited to a carbide substrate, as well as to study the mechanism of wear and failure of carbide tools with coatings under the conditions of stationary cutting. The coating obtained by the method of filtered cathodic vacuum arc deposition (FCVAD). The microstructure of carbide cubstrate with coating on transverse cross-section were investigated, as well as its hardness, strength of the adhesive bond to the substrate, chemical composition and phase composition. The studies of cutting properties of the carbide inserts with developed coating was conducted on a lathe in longitudinal turning of steel C45 (HB 200). Analysis of mechanisms of coated tool wear and failure was carried out, as well as - the study of processes of diffusion and oxidation in the surface layers of the coated substrate.

Improvement of Working Capacity of Carbide Tools for Machining Rail Wheel Pairs

It was found out that under turning wheel pairs, complete tool failure occurs as a result of ductile fracture of cutting wedge. It was also found out that the process of ductile fracture of a tool is governed by creep of local volumes of tool material adjacent to tool contact areas caused by its severe thermo-mechanical load in machining of hard-drawn surfaces of wheel pairs. The method was proposed to effectively reduce thermo-mechanical load on tool contact areas under machining of wheel pairs, while improving heat transfer from the cutting zone, which provides reduction of thermal stress of cutting wedge and improvement of the efficiency of cutting tool.