Simulating the Effect of Microstructure in Metal Sliding and Cutting
Recent experimental discoveries at the mesoscale (100 µm–few mm) in ductile metal sliding and cutting regimes have shown that workpiece surfaces undergo folding by self-contact. The folds subsequently form crack-like features and damage the slid surface. Streaklines of plastic flow associated with surface folding are highly undulating or sinuous. Sinuous flow results in large cutting forces and poor surface finish among other consequences in metal cutting. Thus, understanding the causal mechanism behind surface fold formation and sinuous flow is necessary. It is found from the experiments that microstructure-related property inhomogeneity is a major cause for these phenomena. The aim of this study is to capture surface folding in metal sliding regime in a minimal way and to replicate sinuous flow in the metal cutting regime by introducing microstructure-related property inhomogeneity in the workpiece. In the sliding regime, a square-shaped inhomogeneity is introduced in the workpiece, which is plastically softer or harder than the surrounding substrate. A ‘pseudograin model’ is employed in metal cutting regime, wherein the workpiece surface is divided into a set of ‘grains’ with each grain type plastically different from the others. These models, despite their simplicity, successfully capture all the experimentally observed characteristics of surface folding and sinuous flow in sliding and cutting, thereby establishing the microstructural origin of such complex plastic flows.
KeywordsSliding Cutting Metals Plasticity
This work is supported in part by SERB Grant EMR/2017/002621 from the Department of Science and Technology (DST), Government of India.
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