Creep deformation of dispersion-strengthened copper

Journal Article · Wed May 01 00:00:00 EDT 1996 · Metallurgical Transactions, A

DOI:https://doi.org/10.1007/BF02649859· OSTI ID:260340

Broyles, S E; Anderson, K R; Groza, J R; Gibeling, J C ^[1]

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1. Univ. of California, Davis, CA (United States)

The creep behavior of an internally oxidized, Al{sub 2}O{sub 3} dispersion-strengthened copper alloy, GlidCop Al-15, has been investigated in the temperature range of 745 to 994 K. The results exhibit a high apparent stress exponent (10 to 21) and a high apparent activation energy for creep (253.3 kJ/mole). To describe the creep behavior of this alloy, the Roesler-Arzt model for attractive particle/dislocation interaction is applied. The results are in good agreement with the model when account is taken of the effects of the fine elongated grains and heavily dislocated structures revealed through transmission electron microscopy. The analysis demonstrates that the dislocation/particle interaction is of moderate strength in this alloy, consistent with the observation that the particle/matrix interface is partially coherent. In addition, the analysis reveals that the choice of mechanism and corresponding activation energy for vacancy diffusion has only a small effect on the calculated model parameters. It is argued that the weak dependence of subgrain size on stress demonstrates that creep deformation is particle controlled, rather than subgrain size controlled. In addition, the poorly developed subgrain structure and high dislocation densities are attributed to the presence of the fine oxide particles. Finally, the dependence of rupture time on stress is shown to be consistent with a description of creep fracture based on diffusive cavity growth with continuous nucleation.

• Sponsoring Organization: USDOE
• OSTI ID: 260340
• Journal Information: Metallurgical Transactions, A, Vol. 27, Issue 5; Other Information: PBD: May 1996
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
33 ADVANCED PROPULSION SYSTEMS
70 PLASMA PHYSICS AND FUSION
COPPER
CREEP
PROPULSION SYSTEMS
MATERIALS
THERMONUCLEAR REACTORS
AEROSPACE INDUSTRY
PARTICULATES
ALUMINIUM OXIDES
TEMPERATURE DEPENDENCE
STRESSES
ACTIVATION ENERGY
MATHEMATICAL MODELS
DISLOCATIONS
INTERFACES
VACANCIES
DIFFUSION
GRAIN SIZE