Mechanical behaviour of conventional, Pt- and Pt/Ir-modified NiAl diffusion coatings after thermocyclic exposure at 1100°C

Ceyhun Oskay, Mathias Christian Galetz, Hideyuki Murakami

    Research output: Contribution to journalArticle

    Abstract

    The influence of Pt- and Pt/Ir-modifications on the mechanical properties of NiAl coatings after thermocyclic exposure at 1100°C was investigated. Four-point-bending tests with in-situ acoustic emission measurement were used to determine the fracture strain. After 100 h of exposure a steep increase in fracture strain was observed for the NiAl coating. In contrast, the increase was found to be moderate for modified coatings. For all investigated coatings the fracture strain was correlated with the mean Al-concentration in the diffusion zone, and a moderate increase in the β-phase field with decreasing Al-concentration was found. In the two-phase (β/γ') stability region fracture strain increased steeply. Indentation hardness instead showed a steep decrease within the single β-phase field, but remained almost constant in the two-phase region. Reduced elastic modulus followed a V-curve behaviour, in which a decrease with ongoing Al-depletion in the β-stability region was followed by an increase in the two-phase region.

    Original languageEnglish
    JournalMaterials at High Temperatures
    DOIs
    Publication statusPublished - 2019 Jan 1

    Fingerprint

    Diffusion coatings
    coatings
    Coatings
    Phase stability
    Bending tests
    acoustic emission
    Acoustic emissions
    indentation
    Indentation
    modulus of elasticity
    depletion
    hardness
    Elastic moduli
    Hardness
    mechanical properties
    Mechanical properties
    curves

    Keywords

    • acoustic emission
    • elastic modulus
    • four-point-bending test
    • fracture strain
    • microstructural degradation
    • nanoindentation
    • Pt-modified NiAl
    • thermocyclic exposure

    ASJC Scopus subject areas

    • Ceramics and Composites
    • Condensed Matter Physics
    • Mechanics of Materials
    • Mechanical Engineering
    • Metals and Alloys
    • Materials Chemistry

    Cite this

    @article{d87962cde2024a6d901cf74ddce07cbe,
    title = "Mechanical behaviour of conventional, Pt- and Pt/Ir-modified NiAl diffusion coatings after thermocyclic exposure at 1100°C",
    abstract = "The influence of Pt- and Pt/Ir-modifications on the mechanical properties of NiAl coatings after thermocyclic exposure at 1100°C was investigated. Four-point-bending tests with in-situ acoustic emission measurement were used to determine the fracture strain. After 100 h of exposure a steep increase in fracture strain was observed for the NiAl coating. In contrast, the increase was found to be moderate for modified coatings. For all investigated coatings the fracture strain was correlated with the mean Al-concentration in the diffusion zone, and a moderate increase in the β-phase field with decreasing Al-concentration was found. In the two-phase (β/γ') stability region fracture strain increased steeply. Indentation hardness instead showed a steep decrease within the single β-phase field, but remained almost constant in the two-phase region. Reduced elastic modulus followed a V-curve behaviour, in which a decrease with ongoing Al-depletion in the β-stability region was followed by an increase in the two-phase region.",
    keywords = "acoustic emission, elastic modulus, four-point-bending test, fracture strain, microstructural degradation, nanoindentation, Pt-modified NiAl, thermocyclic exposure",
    author = "Ceyhun Oskay and Galetz, {Mathias Christian} and Hideyuki Murakami",
    year = "2019",
    month = "1",
    day = "1",
    doi = "10.1080/09603409.2019.1591064",
    language = "English",
    journal = "Materials at High Temperatures",
    issn = "0960-3409",
    publisher = "Maney Publishing",

    }

    TY - JOUR

    T1 - Mechanical behaviour of conventional, Pt- and Pt/Ir-modified NiAl diffusion coatings after thermocyclic exposure at 1100°C

    AU - Oskay, Ceyhun

    AU - Galetz, Mathias Christian

    AU - Murakami, Hideyuki

    PY - 2019/1/1

    Y1 - 2019/1/1

    N2 - The influence of Pt- and Pt/Ir-modifications on the mechanical properties of NiAl coatings after thermocyclic exposure at 1100°C was investigated. Four-point-bending tests with in-situ acoustic emission measurement were used to determine the fracture strain. After 100 h of exposure a steep increase in fracture strain was observed for the NiAl coating. In contrast, the increase was found to be moderate for modified coatings. For all investigated coatings the fracture strain was correlated with the mean Al-concentration in the diffusion zone, and a moderate increase in the β-phase field with decreasing Al-concentration was found. In the two-phase (β/γ') stability region fracture strain increased steeply. Indentation hardness instead showed a steep decrease within the single β-phase field, but remained almost constant in the two-phase region. Reduced elastic modulus followed a V-curve behaviour, in which a decrease with ongoing Al-depletion in the β-stability region was followed by an increase in the two-phase region.

    AB - The influence of Pt- and Pt/Ir-modifications on the mechanical properties of NiAl coatings after thermocyclic exposure at 1100°C was investigated. Four-point-bending tests with in-situ acoustic emission measurement were used to determine the fracture strain. After 100 h of exposure a steep increase in fracture strain was observed for the NiAl coating. In contrast, the increase was found to be moderate for modified coatings. For all investigated coatings the fracture strain was correlated with the mean Al-concentration in the diffusion zone, and a moderate increase in the β-phase field with decreasing Al-concentration was found. In the two-phase (β/γ') stability region fracture strain increased steeply. Indentation hardness instead showed a steep decrease within the single β-phase field, but remained almost constant in the two-phase region. Reduced elastic modulus followed a V-curve behaviour, in which a decrease with ongoing Al-depletion in the β-stability region was followed by an increase in the two-phase region.

    KW - acoustic emission

    KW - elastic modulus

    KW - four-point-bending test

    KW - fracture strain

    KW - microstructural degradation

    KW - nanoindentation

    KW - Pt-modified NiAl

    KW - thermocyclic exposure

    UR - http://www.scopus.com/inward/record.url?scp=85063223189&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=85063223189&partnerID=8YFLogxK

    U2 - 10.1080/09603409.2019.1591064

    DO - 10.1080/09603409.2019.1591064

    M3 - Article

    JO - Materials at High Temperatures

    JF - Materials at High Temperatures

    SN - 0960-3409

    ER -