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Earth and Space Sciences · 术语表

什么是 Mechanisms of creep?

又称: dislocation creep · diffusion creep · grain-boundary sliding · pressure solution

Definition 7.2 University Earth and Space Sciences — Year 3 · 第 7 章 — Deformation Mechanisms and Shear Zones

In dislocation creep crystals deform by the glide of dislocations, with climb releasing them from obstacles. In diffusion creep they change shape by the diffusion of atoms, through the lattice (Nabarro–Herring creep) or along the grain boundaries (Coble creep), from the faces under the highest normal stress to those under the lowest. In grain-boundary sliding grains slide past one another along their boundaries, the gaps being closed by diffusion or dislocation creep. In pressure solution the matter dissolves in a fluid film on the faces under high stress and is deposited where the stress is low, or carried away.

Diffusion creep of a grain shortened along . Atoms leave the faces under the highest compression and are added to the faces under the lowest (blue), so the grain flattens and lengthens (grey arrows): (a) through the grain’s interior, Nabarro–Herring creep; (b) along its boundaries, Coble creep.
Diffusion creep of a grain shortened along σ\sigma. Atoms leave the faces under the highest compression and are added to the faces under the lowest (blue), so the grain flattens and lengthens (grey arrows): (a) through the grain’s interior, Nabarro–Herring creep; (b) along its boundaries, Coble creep.
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