Journal Article

PUBDB-2025-02489

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Enhancing the high-cycle fatigue strength of Ti-Al-N coated Ti-6Al-4V by residual stress design

Gitschthaler, A. (Corresponding author)Extern* ; Hahn, R.Extern* ; Zauner, L.Extern* ; Wojcik, P.Extern* ; Fahrnberger, F. ; Hutter, H. ; Davydok, A.Hereon* ; Krywka, C.Hereon* ; Jerg, C. ; Ramm, J. ; Eriksson, A. ; Kolozsvári, S. ; Polcik, P. ; Riedl, H.

2025
Elsevier Science Amsterdam [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.matdes.2025.114445  doi:10.3204/PUBDB-2025-02489

Abstract: Physical vapor deposited coatings are widely utilized as surface protection for metal and ceramic components operating in harsh environments. However, research on the high-cycle fatigue (HCF) life of hard-coated metal substrates has reached contradictory conclusions, leaving it unclear whether ceramic coatings enhance or compromise their fatigue resistance. To improve reliability and extend service life, this study explores the residual stress-dependent influence of arc evaporated TiAlN-based thin films on the fatigue life of Ti-6Al-4V. Therefore, different stress-modifying approaches were implemented, including a substrate bias variation, a Tantalum based alloying strategy, and a specific interlayer design. The combination of high-cycle fatigue tests, synchrotron-based experiments providing depth-resolved stress profiles, and the formulation of a linear-elastic stress-failure model resulted in the following identified relationships: (i) A threshold level in the residual compressive stress state must be present in TiAlN-based coatings to prevent deteriorating HCF performance introduced by failure of the ceramic nitride. (ii) Once the residual compressive stress field is able to shift fatigue crack nucleation into the bulk titanium alloy, the HCF life increases. (iii) The further the residual tensile stress peak is shifted from the bulk material surface — achieved through an optimized residual stress design implementing a metallic interlayer beneath the TiAlN-based top coating — the greater the improvement in HCF strength. Overall, this approach achieved an unprecedented HCF enhancement exceeding 50 % compared to uncoated Ti-6Al-4V (from 420 MPa to 628 MPa at 107 load cycles), highlighting the importance of an in-depth understanding of stress gradients within coating-substrate combinations.

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Contributing Institute(s):

1. DOOR-User (DOOR ; HAS-User)
2. Helmholtz-Zentrum Hereon (Hereon)

Research Program(s):

1. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
2. FS-Proposal: I-20211636 EC (I-20211636-EC) (I-20211636-EC)
3. FS-Proposal: I-20221274 EC (I-20221274-EC) (I-20221274-EC)

Experiment(s):

1. PETRA Beamline P03 (PETRA III)

Appears in the scientific report 2025

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Database coverage:
; ; ; ; Article Processing Charges ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; DOAJ Seal ; Ebsco Academic Search ; Essential Science Indicators ; Fees ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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