Quasicrystalline and crystalline precipitation during isothermal tempering in a 12Cr-9Ni-4Mo maraging stainless steel

Journal Article · Sat Jul 01 04:00:00 EDT 1995 · Acta Metallurgica et Materialia

DOI:https://doi.org/10.1016/0956-7151(94)00461-P· OSTI ID:100647

Liu, P; Stigenberg, A H; Nilsson, J O ^[1]

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1. AB Sandvik Steel, Sandviken (Sweden)

A thorough microstructural investigation has been performed on a high strength maraging steel of the type 12%Cr-9%Ni-4%Mo-2%Cu-1%Ti. The major precipitate formed during isothermal aging at 475 C is a quasicrystalline phase possessing icosahedral symmetry termed R{prime}-phase with a typical chemical composition of 48%Mo-33%Fe-13%Cr-2%Ni-4%Si. At 550 C the major precipitate is trigonal R-phase with a typical composition of 45%Mo-31%Fe-18%Cr-4%Ni-2%Si. At 550 C also Laves phase with a composition of 48%Mo-35%Fe-13%Cr-2%Ni-2%Si could be observed. At both 475 and 550 C an ordered phase termed L-phase precipitated. This minority phase has an ordered face centered cubic (f.c.c.) structure of type L1{sub 0}. Its composition is typically 9%Fe-4%Cr-52%Ni-15%Mo.-16%Ti-4%Al. R{prime}-phase formed at 475 C transformed to R-phase and Laves phase during aging at 550 C. In an analogous manner, R-phase and Laves phase formed at 550 C transformed to R{prime}-phase during subsequent aging at 475 C. This transformation was rationalized by a strong similarity in crystal structure between quasicrystalline R{prime}-phase of icosahedral symmetry and Frank-Kasper phases such as R-phase and Laves phase.

• OSTI ID: 100647
• Journal Information: Acta Metallurgica et Materialia, Journal Name: Acta Metallurgica et Materialia Journal Issue: 7 Vol. 43; ISSN 0956-7151; ISSN AMATEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AGING
CHEMICAL COMPOSITION
CHROMIUM ALLOYS
COPPER ALLOYS
CRYSTAL STRUCTURE
CRYSTALLIZATION
INTERMETALLIC COMPOUNDS
MARAGING STEELS
MICROSTRUCTURE
MOLYBDENUM ALLOYS
NICKEL ALLOYS
PHASE TRANSFORMATIONS
PRECIPITATION
SILICON ADDITIONS
TEMPERATURE DEPENDENCE
TITANIUM ALLOYS