Modeling and Simulating Boron Diffusion: Machinable Materials Application

Abstract

The thesis explores how boron's properties enhance machinable materials through surface hardening processes. It examines relevant boron compounds and analyzes various surface hardening processes, including combined ones, such as borocarburizing, and conflicting ones, like quenching after boriding. Following a comprehensive analysis of surface hardening techniques, the focus narrows to boriding, a thermochemical boron diffusion process categorized as traditional or modern, depending on the complexity and newness of the technique, and the media used, solid, liquid, gas, plasma, ions, and so on. The process is carried out mainly on most metallic machinable materials, such as iron, titanium, and nickel, with limitations to some, like aluminum and copper, while incompatible with nonmetallic ones. Additionally, boriding prefers unalloyed metals and tends to be difficult the higher the alloying becomes. Boride layers, one of the hardest and wear resistant compounds, are synthesized through boron diffusion and layered on the surface of materials. The boriding treatment time and temperatures exposures are the key factors affecting the resulting boride layer thickness, the critical feature affecting the boride layer properties and their compatibility to the demanded application. Accordingly, the research explores different models, empirical, mathematical, of parabolic growth, and even artificial neural networks, to simulate boride layer thicknesses, then provides some comparisons between them for optimization purposes regarding the accuracy and effectiveness of their predictions.