Thin hard coatings are typically employed to improve surface material characteristics such as hardness, wear and contact fatigue resistance, and friction behavior. Their effect on the component fatigue strength may vary, depending on the substrate surface finishing and to the microstructural modification of the base material due to the Physical Vapor Deposition (PVD) process thermal loads, particularly critical for a 7075- T6 low ageing temperature (121 °C) alloy. The present work investigates the effects of a low temperature (180 °C) Tungsten Carbide/Carbon (WC/C) PVD coating, in terms of corrosion protection under fatigue loads. The effects of an aggressive environment over uncoated and coated 7075- T6 hourglass specimens were analyzed, by rotating bending (R = -1) step loading fatigue tests at 2105 cycles. A chemically aggressive external condition has been investigated, considering a methanol environment. Results show a certain protective capability of the WC/C coating, which is however offset by the fatigue strength drop found for coated samples at 2105 cycles. © 2014 The Authors. Published by Elsevier Ltd.

WC/C coating protection effects on 7075- T6 fatigue strength in an aggressive environment

BARAGETTI, SERGIO;GEROSA, RICCARDO;
2014

Abstract

Thin hard coatings are typically employed to improve surface material characteristics such as hardness, wear and contact fatigue resistance, and friction behavior. Their effect on the component fatigue strength may vary, depending on the substrate surface finishing and to the microstructural modification of the base material due to the Physical Vapor Deposition (PVD) process thermal loads, particularly critical for a 7075- T6 low ageing temperature (121 °C) alloy. The present work investigates the effects of a low temperature (180 °C) Tungsten Carbide/Carbon (WC/C) PVD coating, in terms of corrosion protection under fatigue loads. The effects of an aggressive environment over uncoated and coated 7075- T6 hourglass specimens were analyzed, by rotating bending (R = -1) step loading fatigue tests at 2105 cycles. A chemically aggressive external condition has been investigated, considering a methanol environment. Results show a certain protective capability of the WC/C coating, which is however offset by the fatigue strength drop found for coated samples at 2105 cycles. © 2014 The Authors. Published by Elsevier Ltd.
Procedia Engineering
7075- T6; Corrosion; Fatigue; Methanol; Step loading; Thin hard coatings; WC/C; Engineering (all)
File in questo prodotto:
File Dimensione Formato  
Baragetti Gerosa Villa - WCC coating protection effects on 7075-T6 fatigue strength Gerry-Villa.pdf

Accesso riservato

: Publisher’s version
Dimensione 360.1 kB
Formato Adobe PDF
360.1 kB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/1006136
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 7
  • ???jsp.display-item.citation.isi??? 3
social impact