Displacive transformations in near-equiatomic Nb--Ru alloys. II. Energetics and mechanism

Journal Article · Thu Jan 01 04:00:00 EST 1976 · Acta Metall.; (United States)

DOI:https://doi.org/10.1016/0001-6160(76)90144-9· OSTI ID:7138093

Das, B K ^[1]; Stern, E A; Lieberman, D S

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1. Univ. of Illinois, Urbana

The transformation distortions during the ..beta.. ..-->.. ..beta..' and ..beta..' ..-->.. ..beta..'' transformations in near equiatomic Nb--Ru alloys produce phases that have progressively lower symmetry than the CsCl type ..beta.. phase and approach the packing of the hexagonal close packed structure. By the use of a simple approximation, the superposition approximation, a model is developed which explains all of the experimental measurements on this alloy system. The driving force for these transformations is electronic in nature. The Fermi energy ..mu.. of the ..beta.. phase alloys is near a sharp peak in the density of states rho(E). The transformations broaden this peak, lowering rho(..mu..) and the energy of the phase. The significant experimental measurements accounted for by this model are the variation of magnetic susceptibility with phase and Ru content, the variation of transformation temperatures and transformation distortion with Ru composition, and distortion in the ..beta..'' phase with temperature and Ru composition.

• OSTI ID: 7138093
• Journal Information: Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 24:1; ISSN AMETA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOY SYSTEMS
ALLOYS
BINARY ALLOY SYSTEMS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ENERGY LEVELS
FERMI LEVEL
HCP LATTICES
HEXAGONAL LATTICES
KINETICS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
NIOBIUM ALLOYS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PLATINUM METAL ALLOYS
REACTION KINETICS
RUTHENIUM ALLOYS