The role of specimen thickness in the fracture toughness and fatigue crack growth resistance of nanocrystalline platinum films

Roi A. Meirom, Trevor Edward Clark, Christopher L. Muhlstein

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Most empirical studies and numerical simulations of fatigue damage accumulation mechanisms for metals with nanoscale grains usually invoke grain boundary-mediated processes. However, our recent studies of ∼500 nm platinum films showed that when the grain morphology is stable in the presence of high stresses and/or elevated temperatures the slip of dislocations is of primary interest. These thin film metals exhibit low fracture toughness and inferior resistance to fatigue crack growth when compared to conventional microscale grained bulk forms of the materials. In this manuscript we explore how sample form (thickness) contributes to the fracture and fatigue crack growth behavior of platinum thin films. When the thickness of the films was doubled to ∼1 μm the tensile yield and ultimate strengths were slightly depressed (yield strength ∼1.3 GPa, ultimate tensile strength ∼1.45 GPa). However, the fracture toughness markedly improved (K q value 25.4 MPa √m) and the fatigue crack growth resistance was very similar to bulk forms (power law exponent m ≈ 3.9). The progression and type of damage shows that sample form makes a critical and distinct contribution to the fatigue crack growth mechanisms in nanograined metals.

Original languageEnglish (US)
Pages (from-to)1408-1417
Number of pages10
JournalActa Materialia
Volume60
Issue number3
DOIs
StatePublished - Feb 1 2012

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Platinum
Fatigue crack propagation
Fracture toughness
Metals
Thin films
Fatigue damage
Yield stress
Grain boundaries
Tensile strength
Computer simulation
Temperature

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

Cite this

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The role of specimen thickness in the fracture toughness and fatigue crack growth resistance of nanocrystalline platinum films. / Meirom, Roi A.; Clark, Trevor Edward; Muhlstein, Christopher L.

In: Acta Materialia, Vol. 60, No. 3, 01.02.2012, p. 1408-1417.

Research output: Contribution to journalArticle

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