Video Experimental Relacionado
Updated: Aug 10, 2026
08:43
Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors
Published on: November 7, 2016
Factores de control para la transición de frágil a dúctil en los cristales únicos de tungsteno
1Max-Planck-Institut fur Metallforschung, Seestrasse 92, 70174 Stuttgart, Germany.
Science (New York, N.Y.)
|November 13, 1998
Resumen
La transición de los materiales de la fractura dúctil a la frágil es dependiente de la temperatura. Los experimentos muestran que la dislocación de la nucleación es clave para la resistencia a la fractura, pero la movilidad controla la transición general.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Mecánica de los Sólidos Mecánica de los Sólidos
- La metalurgia física es la metalurgia física.
Sus antecedentes:
- El rendimiento del material en aplicaciones estructurales está limitado por la transición de dúctil a frágil.
- Se entiende que esta transición se rige por la movilidad de la dislocación o la nucleación.
Objetivo del estudio:
- Investigar los roles de la nucleación y la movilidad de la dislocación en la transición de dúctil a frágil.
- Para proporcionar pruebas experimentales de cristales simples de tungsteno.
Principales métodos:
- Experimentos de fractura en cristales únicos de tungsteno.
- Análisis de la tenacidad a la fractura en el régimen semi-frágil.
Principales resultados:
- La nucleación por dislocación es importante para la tenacidad a la fractura en el régimen semi-frágil.
- La movilidad de la dislocación, no la nucleación, generalmente controla la transición de dúctil a frágil.
Conclusiones:
- El estudio aclara los mecanismos que rigen el comportamiento de fractura dependiente de la temperatura de los materiales.
- La comprensión de estos mecanismos es crucial para el diseño de materiales estructurales robustos.
Videos de Conceptos Relacionados
01:25Crystal Growth: Principles of Crystallization
Crystallization is a phase transformation process in which crystals are precipitated from a supersaturated solution or formed from other sources. During crystallization, atoms or molecules arrange themselves into a well-defined, rigid crystal lattice to minimize energy.
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent – the...
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent – the...
01:21Polymer Classification: Crystallinity
Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
01:21Plastic Behavior
A material's elastic behavior is characterized by the disappearance of stress once the load is removed, allowing the material to return to its original state. However, when stress surpasses the yield point, yielding commences, marking the onset of plastic deformation or permanent set. This change from elastic to plastic behavior is influenced by the peak stress value and the duration before the load is removed. An intriguing observation occurs when a specimen is loaded, unloaded, and reloaded.
01:25Imperfections in Crystal Structure: Point, Line and Plane Defects
A perfect crystal, in theory, has a uniform structure with the same unit cell and lattice points throughout. However, any deviation from this periodic arrangement is known as an imperfection or defect. These defects can be categorized into three types: point, line, and plane defects.Point defects occur when there is a deviation from the ideal due to missing atoms, displaced atoms, or additional atoms. These imperfections might occur due to imperfect packing during crystallization or because of...
01:26Imperfections in Crystal Structure: Stoichiometric Point Defects
Schottky defects arise when some lattice points in a crystal, such as those in NaCl, remain unoccupied, creating lattice vacancies without disturbing the overall electrical neutrality of the crystal. This defect is common in ionic crystals where the positive and negative ions are similar in size, as seen in sodium chloride and cesium chloride. The presence of Schottky defects enables the crystal to conduct electricity to a small extent through an ionic mechanism. Electric fields cause nearby...
01:28Classification and Mechanical Properties of Synthetic Polymers
Synthetic polymers are classified as elastomers, fibers, or plastics based on their crystallinity. Crystallinity, the degree of long-range order in the solid state, influences the mechanical properties (stretching or contracting) of elastomers. Elastomers are flexible polymers that can expand or contract easily upon the application of an external force. They have numerous crosslinks that pull them back into their original shape when stress is removed. Silicones, for instance, are highly elastic...