Micro-scratching behavior of heat-treated cutting chips of Inconel 718. (August 2022)

• Record Type: Journal Article
• Authors: Yadav, Prabhat Chand; Setia, Prince; Sahu, Sandeep
• Is Part Of: Materials today communications. Volume 32(2022)
• Publication Date: 2022-08
• Subjects: Inconel 718 -- Severe plastic deformation -- Heat-treatment -- Mechanical property -- Wear behavior -- Scratch test; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2022.104007
• Languages: English
• ISSNs: 2352-4928

Abstract

Abstract: The present work investigates the micro-scratching behavior of Inconel 718 alloy processed by machining and subsequent heat-treatment. As-machined chips were heat-treated at 700 °C, 800 °C, and 900 °C, all for a short duration of 15 min, followed by water quenching to allow the precipitation of γ I and γ II phases. Microstructural analysis of the processed Inconel 718 chips revealed the formation of nano-size precipitates either along the grain boundaries or at the triple junctions, which contributed to the improved mechanical property compared to the solution annealed sample. It was found that the chips heat-treated at 700 °C possessed the highest average hardness (548 Kgf/mm 2 ) among all the sample conditions. High hardness of as-machined chips and short heat-treatment at 700 °C led bimodal microstructure and precipitation pining resulting in maximum wear resistance compared to other heat-treatment conditions. Subsequently, to verify the outcome, worn surface analysis of as-machined and subsequently heat-treated chips was performed. Comparatively, larger size cracks in sample heat-treated at 900 °C attributed to a high cracking scratch zone in the processed material, i.e., less wear resistance, whereas no/nominal crack in as-machined chips and chips heat-treated at 700 °C attributed to no cracking scratch zone. Graphical Abstract: ga1 Highlights: Current work demonstrates the potency of the plane strain machining in governing the wear characteristics of Inconel 718. A combination of plane strain machining and short heat-treatment at 700 °C significantly improves wear resistance. Improvement in wear resistance of as-machined and short heat-treated sample at 700 °C is attributed to bimodal grain size distribution and grain boundary pinning by γ I and γ II nano-precipitates.