The effect of the work roll topography on the surface deformation of aluminum alloys during hot rolling was examined with the use of a rolling tribo-simulator. AISI 52100 steel work rolls with two surface conditions, smooth (polished to a surface roughness (R a ) of 0.01 μm) and rough (WC-coated with a surface roughness (R a ) of 5.68 μm), were used to hot roll Al-Mg alloy samples under similar conditions for a rolling schedule of 10 passes. The surface of the rolled samples reflected the work roll surface morphology. Surface damage for the smooth rolled samples included cracks, while shingles and grooves were observed on the rough rolled samples. Cross-sectional examination revealed cracks extended to depths above 8 μm for the rough rolled samples, while for the smooth rolled samples, cracks were 1.5 μm deep. The oxide-rich near-surface layer formed on the rough rolled surfaces was discontinuous. In contrast, the near-surface generated by the smooth roll was continuous, and near-surface damage was uniform in comparison. A nanocrystalline grain structure was observed at the near-surface region beneath the oxide-rich area for the smooth rolled samples, which extended to shingles on the rough rolled samples. The nanocrystalline nature of the near-surface region was attributed to the high strains imposed by the work roll, while the effect of the rough roll was surmised to include the formation of shingles, the redistribution of surface oxide, and the enhancement of the near-surface damage.
The introduction of additives enhances the friction and wear reduction properties of cutting fluids (CFs) as well as aids in improving the surface quality of the machined parts. This study examines the tribological behavior of polymer-based and phosphorus-based additives introduced into cutting fluids for the machining of Al-Mn alloys. Ball-on-disc tests were used to evaluate the coefficient of friction (COF) and lubrication failure temperature to study the performance of the additives in the cutting fluids. Surface characterization was performed on the sliding tracks induced on the Al-Mn disc surfaces and used to propose the wear and friction reduction mechanisms. The polymer-based additive possessed a higher temperature at which lubrication failure occurred, displayed comparable COF at a lower temperature under certain conditions, and possessed a steadier tribological behavior. However, the phosphorus-based additive was observed to display lower COF and wear damage from 200 °C till failure. The lower COF values for the phosphorus-based additive at 200 °C corresponded with lower surface damage on the Al-Mn surface. The phosphorus-based additive’s performance at 200 °C could be attributed to the forming of a phosphorus-rich boundary layer within the sliding wear track, resulting in less surface damage on the Al-Mn surface and lower material transfer to the counterface steel ball surface.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.