Characterization of the Inhomogeneous Distribution of Light Elements in Ferritic Heat-Resistant Steels by Secondary Ion Mass Spectrometry

  • Suzuki Shigeru
    Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
  • Shishido Rie
    Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
  • Tanaka Tomohito
    Nippon Steel & Sumitomo Metal Corporation, Advanced Technology Research Laboratories
  • Abe Fujio
    National Institute for Materials Science

抄録

The addition of a small amount of boron and nitrogen is known to improve the creep strength and life of ferritic heat-resistant steels. These light elements are thought to be distributed in the microstructures in a complicated manner during the heat treatment and creep of these steels. In order to understand the influence of the light elements on the mechanical properties of ferritic heat-resistant steels, a microscopic distribution analysis of the light elements is of importance. In this study, two types of secondary ion mass spectrometry (SIMS) methods were used to investigate the measurement conditions for analyzing secondary ions derived from boron and nitrogen in steels. In dynamic SIMS with a quadrupole analyzer, boron in the samples was effectively detected as BO2 ions under irradiation with primary O2+ ions. From the time-of-flight (ToF) SIMS using a focused primary Bi32+ ion beam coupled with the exposure of the sample to a low partial pressure of oxygen, it was suggested that boron is enriched in M23C6 carbides in the steels and it may be, more or less, segregated at prior austenite grain boundaries with a moderate amount of nitrogen during normalizing. It was also demonstrated that nitrogen is precipitated as boron nitride in steels containing an excess amount of boron and nitrogen. The characteristics of the distribution of boron and nitrogen in the steels are discussed on the basis of the thermodynamic properties of these elements in the steels.

収録刊行物

被引用文献 (3)*注記

もっと見る

参考文献 (23)*注記

もっと見る

関連プロジェクト

もっと見る

詳細情報 詳細情報について

問題の指摘

ページトップへ