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- Grain boundary sliding (GBS) is a material deformation mechanism where grains slide against each other. This occurs in polycrystalline material under external stress at high homologous temperature (above ~0.4) and low strain rate and is intertwined with creep. Homologous temperature describes the operating temperature relative to the melting temperature of the material. There are mainly two types of grain boundary sliding: Rachinger sliding, and Lifshitz sliding. Grain boundary sliding usually occurs as a combination of both types of sliding. Boundary shape often determines the rate and extent of grain boundary sliding. Grain boundary sliding is a motion to prevent intergranular cracks from forming. Keep in mind that at high temperatures, many processes are underway, and grain boundary sliding is only one of the processes happening. Therefore it is not surprising that Nabarro Herring and Coble creep is dependent on grain boundary sliding. During high temperature creep, wavy grain boundaries are often observed. We can simulate this type of boundary with a sinusoidal curve, with amplitude h and wavelength λ. Steady-state creep rate increases with rising λ/h ratios. At high λ and high homologous temperatures, grain boundary sliding is controlled by lattice diffusion (Nabarro-Herring mechanism). On the other hand, it will be controlled by grain boundary diffusion (Coble Creep). Additionally, when λ/h ratios are high, it may impede diffusional flow, therefore diffusional voids may form, which leads to fracture in creep. Many people have developed estimations for the contribution of grain boundary sliding to the total strain experienced by various groups of materials, such as metals, ceramics, and geological materials. Grain boundary sliding contributes a significant amount of strain, especially for fine grain materials and high temperatures. It has been shown that Lifshitz grain boundary sliding contributes about 50-60% of strain in Nabarro–Herring diffusion creep. This mechanism is the primary cause of ceramic failure at high temperatures due to the formation of glassy phases at their grain boundaries. (en)
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- 21728 (xsd:nonNegativeInteger)
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- Grain boundary sliding (GBS) is a material deformation mechanism where grains slide against each other. This occurs in polycrystalline material under external stress at high homologous temperature (above ~0.4) and low strain rate and is intertwined with creep. Homologous temperature describes the operating temperature relative to the melting temperature of the material. There are mainly two types of grain boundary sliding: Rachinger sliding, and Lifshitz sliding. Grain boundary sliding usually occurs as a combination of both types of sliding. Boundary shape often determines the rate and extent of grain boundary sliding. (en)
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- Grain boundary sliding (en)
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