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Pressure dependence of Zr diffusion in the equiatomic B.C.C. TiZr alloy
Author(s) -
Büscher M.,
Herzig C.,
Köhler U.,
Mehrer H.,
Lojkowski W.
Publication year - 1992
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221740205
Subject(s) - alloy , diffusion , materials science , arrhenius equation , thermodynamics , condensed matter physics , activation energy , metallurgy , crystallography , chemistry , physics
Positive as well as negative activation volumes have been measured in the past for self‐diffusion in “anomalous” b.c.c. metals. To contribute to this problem and to obtain further information on the diffusion mechanism in b.c.c. transition metals the pressure dependence of diffusion of 95 Zr is measured in the equiatomic b.c.c. TiZr alloy at 1003 and 1493 K in the pressure range up to 14.4 × 10 8 Pa. The rather small but positive activation volumes Δ V = 0.31 ± 0.06Ω and Δ V = 0.35 ± 0.10Ω, respectively, are obtained. The results are in conflict with negative Δ V values reported for this alloy by Smirnov et al., however, they agree very well with Δ V of self‐diffusion in β‐Ti. Within the limits of error Δ V is independent of temperature which indicates that only one diffusion mechanism is operating despite of the strongly curved Arrhenius relations of 95 Zr and 44 Ti diffusion in TiZr alloy. The present results confirm a monovacancy mechanism in group IVA b.c.c. metals.