Ni 基単結晶超耐熱合金のクリープ破断強度に及ぼす時効処理条件の影響

概要

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Creep-rupture strengths and microstructures of two single crystal superalloys, NASAIR100 and CMSX-3, heat-treated at various conditions were investigated. As aging temperature was raised, γ′ particles coarsened and its morphology changed as follows ; irregular cube→regullar cube→rounded cube→plate. Optimum creep-rupture strength at 1040℃ and 760℃ was obtained in the specimens in which the initial γ′ morphology was regularly cuboidal. The reason was related to the degree of perfection of "rafted" structure during 1040℃ creep and to the change in the deformation mechanism from cutting to by-passing model during 760℃ creep. The morphological change of γ′ particles is strongly influenced by the lattice mismatch between γ and γ′ phases, thus the optimum heat-treatment condition varies with alloys. For an alloy with larger absolute value of lattice mismatch, heat-treatment at lower temperature is desirable and for an alloy with smaller one, heat-treatment at higher temperature is available.
社団法人日本鉄鋼協会の論文
1989-06-01