Anelastic study of screw-dislocation motion in high-purity niobium

Journal Article · Thu Oct 01 00:00:00 EDT 1992 · Acta Metallurgica; (United States)

DOI:https://doi.org/10.1016/0956-7151(92)90334-B· OSTI ID:6907190

Mizubayashi, H; Morita, M; Kakiharia, T; Okuda, S ^[1]

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1. Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science

For the [gamma] peak [the kink pair formation (KPF) on screw dislocations] in high-purity Nb, the stress ([sigma]) dependence of the activation enthalpy (H[sub KPF]) and the pre-exponential factor ([nu][sub 0]) of the reciprocal of the relaxation time was investigated using anelastic creep. H[sub KPF] at [sigma] = 0, i.e. 2H[sub k] (H[sub k] = the enthalpy of an isolated single kink), was found as 0.63 [plus minus] 0.02 eV with log[[nu][sub 0] (s[sup 1[minus]])] = 13.6 [plus minus] 0.5. [nu][sub 0] decreased with increasing [sigma] as well as H[sub KPF], by about two orders at [sigma] = 16 MPa: When In[[nu] [sub 0]/[nu] = 0] is plotted against (2H[sub k - H][sub KPF])2H[sub k][proportional to] ([sigma]/[sigma][sub p])[sup 1/2] with [sigma][sub p] = the Peierls stress, a good similarity can be found between the present result in Nb and the result reported in Fe. In this paper surmise that the decrease in [nu][sub 0] with increasing [sigma] is mainly associated with a change in the entropy factor associated with KPF.

• OSTI ID: 6907190
• Journal Information: Acta Metallurgica; (United States), Journal Name: Acta Metallurgica; (United States) Vol. 40:10; ISSN 0001-6160; ISSN AMETAR
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360103 -- Metals & Alloys-- Mechanical Properties
ACTIVATION ENERGY
CREEP
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIFFERENTIAL EQUATIONS
DISLOCATIONS
ELEMENTS
ENERGY
ENTROPY
EQUATIONS
EQUATIONS OF MOTION
IMPURITIES
LINE DEFECTS
MECHANICAL PROPERTIES
METALS
NIOBIUM
PARTIAL DIFFERENTIAL EQUATIONS
PHYSICAL PROPERTIES
RELAXATION
SCREW DISLOCATIONS
STRESS RELAXATION
STRESSES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
VARIATIONS