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Out-of-Equilibrium Thermodynamics
Published in Pier Luigi Gentili, Untangling Complex Systems, 2018
The chemical affinity A is the difference between the sum of the chemical potentials of the reagents and the sum of the chemical potentials of the products; wherein every chemical potential is multiplied by its stoichiometric coefficient. When A > 0 (it means the sum of the chemical potentials of the reagents is larger than that of the products), the reagents spontaneously transform to the products. The species at higher potentials transform into other species having lower potentials. This behavior is similar to the phenomenon of a ball that slides along a well from a point at high potential energy to the minimum of the well (see Figure 3.4).
Optimization of process parameter in AI7075 turning using grey relational, desirability function and metaheuristics
Published in Materials and Manufacturing Processes, 2023
Dillip Kumar Mohanta, Bidyadhar Sahoo, Ardhendu Mouli Mohanty
Al7075 has extreme strength and corrosion resistance, and is frequently used in industrial machinery, powerful guns and other applications.[1] Though aluminum alloys are machined easily and cost-effectively, their low melting point and chemical affinity make it challenging to work with, thus creating an enviable problem in determining the ideal machining process parameters while machining due to staggered frictional heat and chip tool adhesion.[2] This has an impact on the surface quality, cutting force and temperature. In comparison to traditional machining, accuracy and repeatability of CNC lathes are much superior and efficient. Necessity for machining of aluminum, sharp cutting edge and prevention of built up edge is a priority, so in recent days tungsten carbide tools as coated inserts are used widely with a positive rake.
Performance evaluation of process parameters using MCDM methods for Titanium Alloy (Ti6al4v) in turning operation
Published in Australian Journal of Mechanical Engineering, 2023
Sushil V Ingle, Dadarao N Raut
Titanium and its alloys have outstanding corrosion resistance, superior biocompatibility, notable tissue inertness, good weldability, and other properties (Bhaumik, Divakar, and Singh 1995; von Turkovich and Durham 1982). These alloys have several uses in a variety of industries, including the chemical processing industry, the oil and gas industry, the marine and aviation industries, and the medical sector (2005). The aforementioned intrinsic qualities and practicality of titanium alloys compel researchers to investigate and scrutinise a variety of these alloys’ machining features. Recent years have seen increased interest from other commercial and industrial sectors in the studies on the machinability characteristics of these alloys. On the other hand, the restricted use of titanium alloys is caused by their high initial cost and extraction process challenges. Additionally, due to the lower productivity, these alloys can only be machined at a limited range of cutting rates (about 30–60 m/min) due to their high chemical affinity and poor heat conductivity.
On wear of WC–Co cutting inserts in turning of Ti6Al4V – a study of wear surfaces
Published in Tribology - Materials, Surfaces & Interfaces, 2021
Petra Olander, Jannica Heinrichs
In Refs. [1,5], some important criteria of a successful tool material for cutting titanium are mentioned. To limit problems with heat generation, a high hot hardness, high thermal conductivity and low chemical affinity to titanium is needed (also at elevated temperatures). To minimize the risks associated with chip formation, a high toughness, fatigue resistance and high compressive strength is required. There is no available material that fulfils all of these criteria, but cemented carbide is performing well in many of the above-mentioned areas. Although uncoated cemented carbides have proven their superiority in the application, the wear is relatively high and is reported to be characterized by notching, thermal diffusion, chemical reaction, crater wear, abrasion and chipping, and subsequent catastrophic failure is not uncommon [1,4,8,9].