The effect of Mn on the activities of Fe, Ni, and Cr in an Fe-Ni-Cr base alloy
- Bureau of Mines, Washington, DC (United States). Div. of Mineral Commodities
A combination Knudsen cell-mass spectrometer apparatus developed by the Bureau of Mines is accurate enough to permit the activity of many alloy components to be measured directly as the ratio of the ion currents of an appropriate isotope evaporated from the alloy and from the pure component. This apparatus has been used to determine the activities of Fe, Ni, and Cr as functions of temperature in 71Fe-20Ni-6Cr-3Mn (at. pct). A comparison of the data with data obtained earlier from other Fe-Ni-Cr base alloys indicates that partial substitution of Mn for Cr causes the activity coefficient of Fe to decrease and to deviate negatively above 1,550 K. The activity coefficient of Ni is markedly increased by the substitution decreases both the activity coefficient of Cr and the temperature dependence of this coefficient. The oxidation behavior of Fe-Ni-Cr base alloys, the stability of the austenitic phase in such alloys, and the Ni equivalent of Mn are discussed in light of these changes in activity coefficient.
- OSTI ID:
- 5631297
- Journal Information:
- Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Vol. 24:11; ISSN 0360-2133
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHROMIUM ALLOYS
THERMODYNAMIC ACTIVITY
IRON BASE ALLOYS
MANGANESE
METALLURGICAL EFFECTS
MANGANESE ALLOYS
NICKEL ALLOYS
AUSTENITE
MATERIAL SUBSTITUTION
OXIDATION
REACTION KINETICS
STABILITY
VAPOR PRESSURE
ALLOYS
CARBON ADDITIONS
CHEMICAL REACTIONS
ELEMENTS
IRON ALLOYS
KINETICS
METALS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
360104* - Metals & Alloys- Physical Properties