- •1.The solid solution – chemical imperfection
- •2. Point defects – zero- dimensional imperfections
- •3 Linear defects, or dislocations – one-dimensional imperfection
- •4 Planar defects – two-dimensional imperfections
- •5 Microscopy
- •5.1 Electron microscope
- •5.2 Scanning electron microscope (sem)
- •Abstract
Abstract
That is no material can be prepared without some degree of chemical impurity. The impurity atoms or ions in the resulting solid solution serve to alter the structural regularity of the ideally pure material.
The simplest type of flaw is the point defect, for example, a missing atom (vacancy). This type of flaw is the inevitable result of the normal thermal vibration of atoms in any solid at a temperature above absolute zero.
Linear defects, or dislocations, follow an extended and sometimes complex path through the crystal structure.
Planar defects represent the boundary between a nearly perfect crystalline region and its surroundings.
Glossary:
substitutional solid solution – твердый раствор замещения,
Interstitial solution – твердый раствор внедрения,
Point defects – точечные дефекты, missing atoms – пропущенные атомы, vacancies – вакансии, extra atoms- дополнительные атомы, interstitialcies- междоузлие.
Linear defects or dislocations – линейные дефекты или дислокации, extra half-plane of atoms – дополнительная полуплоскость, Burgers vector – вектор Бургера.
Planar defects – плоскостные дефекты, boundary surface – граница поверхности, Twin boundaries – границы двойникования, mirror-image regions – зеркально-отображающие области, The predominant microstructural feature for many engineering materials is grain structure, where each grain is a region with a characteristic crystal structure orientation.
grain-size number (G) - размер зерна, Noncrystalline solids – некристаллические твердые тела, long-range order (LRO) – симметрия дальнего порядка, short-range order (SRO) – симметрия ближнего порядка.
Quasicrystals – квазикристаллы, intermediate state – промежуточное состояние, fivefold symmetry – симметрия пятого порядка, icosahedral phases- икосаэдрические фазы.
observing structural order and disorder – наблюдение за структурной упорядоченностью и разориентацией.