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Effects of constrained groove pressing, severe shot peening and ultrasonic nanocrystal surface modification on microstructure and mechanical behavior of S500MC high strength low alloy automotive steel

Karademir, I ; Sharif University of Technology | 2021

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  1. Type of Document: Article
  2. DOI: 10.1016/j.apsusc.2020.147935
  3. Publisher: Elsevier B.V , 2021
  4. Abstract:
  5. S500MC high strength low alloy automotive steel is exposed to bulk severe plastic deformation (SPD) via constrained groove pressing (CGP) and surface severe plastic deformation (S2PD) via severe shot peening (SSP) and ultrasonic nanocrystal surface modification (UNSM). SSP and UNSM could create a nanocrystallization layer till 50–100 µm away from outmost surface. EBSD investigations showed average nano-grain size obtained via SSP and UNSM was found to be below 100 nm regime. The strength was improved via 1st to 4th pass of CGP, but elongation percentage decreased abruptly. UNSM achieves both strength-ductility improvement with gradient structure. SSP improves the total elongation however a slight decrease on strength is observed. SSP and UNSM showed better wear and friction resistance particularly at lower loads compared to CGP and untreated specimens. Nevertheless, wear and friction behavior at higher loads showed better responses for Bulk-SPD applications regardless of pass numbers. The frictional load increase played a detrimental role in removing a nanocrystallization surface layer and diminishing the positive influence of SSP and UNSM. © 2020 Elsevier B.V
  6. Keywords:
  7. Aluminum sheet ; Friction ; High strength alloys ; High-strength low-alloy steel ; Nanocrystallization ; Nanocrystals ; Plastic deformation ; Shot peening ; Wear of materials ; Wear resistance ; Constrained groove pressing ; Ductility improvement ; Elongation percentage ; High strength low alloys ; Mechanical behavior ; Severe plastic deformations ; Ultrasonic Nanocrystal Surface Modification (UNSM) ; Ultrasonic nanocrystal surface modifications ; Nanocrystalline alloys
  8. Source: Applied Surface Science ; Volume 538 , 2021 ; 01694332 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0169433220326921