Phase chemistry and precipitation reactions in maraging steels: Part 4. Discussion and conclusions

Journal Article · Tue Jun 01 04:00:00 EDT 1993 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

DOI:https://doi.org/10.1007/BF02668193· OSTI ID:6209515

Sha, W ^[1]; Cerezo, A; Smith, G D.W. ^[2]

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1. Cambridge Univ. (United Kingdom). Department of Materials Science and Metallurgy
2. Univ. of Oxford (United Kingdom). Department of Materials

This article summarizes studies of phase chemistry and precipitation reactions in a variety of maraging steels. The roles of different phases and alloying elements are investigated by comparing the behavior of different steels. The phases considered are Ni[sub 3]Ti, Fe[sub 7]Mo[sub 6] [mu] phase, Fe[sub 2]Mo Laves phase, [omega] phase, Ti[sub 6]Si[sub 7]Ni[sub 16]G phase, Z phase, austenite, and [alpha] matrix. The alloying elements discussed are Ti, Al, Mo, Si, Mn, Ni, Cr, and Co. By comparing the aging behavior of both commercial steels and model alloys, a major role of Co is confirmed to be the lowering of the matrix solubility of Mo. Of the two main hardening elements in maraging steels (namely, Ti and Mo), Ti is much more active than Mo in the very early stage of precipitation. The main Mo-rich precipitate found in this work was Fe[sub 7]Mo[sub 6][mu] phase instead of Laves phase. The precipitation of Mo is modified by the presence of Ti. [omega] phase appears only in Ti-free alloys, especially when aged at a low temperature. The quantity of Ni-containing precipitates and the presence of Cr in the steels change the austenite reversion behavior. Other phases, such as G phase and Z phase, contribute to age hardening in different types of maraging alloys.

• OSTI ID: 6209515
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Journal Name: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States) Vol. 24A:6; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
360102* -- Metals & Alloys-- Structure & Phase Studies
AGE HARDENING
AGING
ALLOYS
ALUMINIUM
AUSTENITE
CARBON ADDITIONS
CHROMIUM
COBALT
ELEMENTS
HARDENING
INTERMETALLIC COMPOUNDS
IRON ALLOYS
IRON BASE ALLOYS
KINETICS
MANGANESE
MARTENSITIC STEELS
METALLURGICAL EFFECTS
METALS
MOLYBDENUM ALLOYS
NICKEL
NICKEL ALLOYS
PHASE STUDIES
PHASE TRANSFORMATIONS
PRECIPITATION
SEMIMETALS
SEPARATION PROCESSES
SILICON
SILICON ALLOYS
STEELS
TITANIUM
TITANIUM ALLOYS
TRANSITION ELEMENTS