Strengthening of heat resistant martensitic steel by Cu addition

T. Tsuchiyama, Y. Futamura, S. Takaki

    Research output: Contribution to journalConference articlepeer-review

    10 Citations (Scopus)

    Abstract

    Microstructure and creep deformation behavior were investigated in martensitic 9%Cr-(0-4)%Cu steels, and the strengthening mechanism by Cu was discussed in terms of microstructural change during creep deformation. As-quenched specimens have typical lath-martensitic structure. Cu addition gives no influence on the morphology of martensite-laths, but austenite grains tend to be refined with increasing the Cu content. As a result of creep testing for the quenched specimens with a same grain size, it was found that minimum creep rate is greatly lowered and rupture time are prolonged with increasing the Cu content. TEM observations of a creep-deformed 9%Cr-4%Cu steel revealed that dislocations attractively interact with ε-Cu particles within laths, and also lath boundaries are pinned by the ε-Cu particles. Through these interactions between dislocations or lath boundaries and ε-Cu particles, recovery in martensitic structure is greatly retarded, and dislocation density is kept higher during creep deformation. But once the pinning force by ε-Cu particles falls below the applied stress, the recovery rapidly proceeds and the strain rate is accelerated.

    Original languageEnglish
    Pages (from-to)411-418
    Number of pages8
    JournalKey Engineering Materials
    Volume171-174
    Publication statusPublished - 2000
    EventProceedings of the 1999 8th International Conference on Creep and Fracture of Engineering Materials and Structures - Tsukuba, Jpn
    Duration: Nov 1 1999Nov 5 1999

    All Science Journal Classification (ASJC) codes

    • Mechanics of Materials
    • Mechanical Engineering
    • General Materials Science

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