Control over Multi-Scale Self-Organization-Based Processes under the Extreme Tribological Conditions of Cutting through the Application of Complex Adaptive Surface-Engineered Systems

Abstract

This paper features a comprehensive analysis of various multiscale selforganization processes that occur during cutting. A thorough study of entropy production during friction has uncovered several channels of its reduction that can be achieved by various selforganization processes. These processes are (1) self-organization during physical vapor deposition PVD coating deposition on the cutting tool substrates; (2) tribofilm formation caused by interactions with the environment during operation, which consist of the following compounds: thermal barriers; Magnéli phase tribo-oxides with metallic properties at elevated temperatures, tribo-oxides that transform into a liquid phase at operating temperatures, and mixed action tribo-oxides that serve as thermal barriers/lubricants, and (3) multiscale selforganization processes that occur on the surface of the tool during cutting, which include chip formation, the generation of adhesive layers, and the buildup edge formation. In-depth knowledge of these processes can be used to significantly increase the wear resistance of the coated cutting tools. This can be achieved by the application of the latest generation of complex adaptive surface-engineered systems represented by several state-of-the-art adaptive nano-multilayer PVD coatings, as well as high entropy alloy coatings (HEAC).

Accelerated Tribo-Films Formation in Complex Adaptive Surface-Engineered Systems under the Extreme Tribological Conditions of Ultra-High-Performance Machining

“…A microscopic volume seizure (see TEM cross-section image, Figure 1) was observed at the very beginning of cutting (only after 2 min, Figure 1). This is an example of a stick-slip process, which occurs during chip formation and involves a self-organized critical phenomenon [11,12]. The forming adhesive layer of workpiece material gradually transforms into a BUE (buildup edge) [11,12].…”

“…This is an example of a stick-slip process, which occurs during chip formation and involves a self-organized critical phenomenon [11,12]. The forming adhesive layer of workpiece material gradually transforms into a BUE (buildup edge) [11,12]. A strong adaptive response takes place within the layer of the analyzed complex adaptive system represented by a nano-multilayer TiAlCrSiYN/TiAlCrN PVD coating.…”

“…In (Ti-Al)N-based coatings, a relatively low wear rate of the tool is caused by the predominant formation of aluminum oxide (Al 2 O 3 ) tribo-films on the friction surface. With the predominant formation of titanium oxide (TiO 2 ), intense tool/workpiece adhesive interaction occurs, which leads to tool wear [11]. As a result of this situation, mainly titanium oxide wears out.…”

“…Coming from the field of tribology, a typical extra high-speed machining process develops on the edge of chaos [9,10]. The analyzed complex adaptive system is represented by specially designed thin-film nanomaterials (Physical vapor deposited (PVD) coatings), capable of withstanding such extreme conditions [11]. Multiple closely interrelated processes, in particular that of self-organization, and self-organized criticality were investigated to gain a better understanding of the observed complex phenomena [12].…”