Amorphous metals, or metallic glasses, are alloys with a disordered, non-crystalline atomic structure, similar to that of common glass. This is achieved by cooling the molten alloy at extremely high rates (e.g., [latex]10^6[/latex] K/s), preventing the atoms from organizing into a regular crystal lattice. Lacking grain boundaries, they exhibit unique properties like high strength, elasticity, and résistance à la corrosion.
The creation of an amorphous metal requires bypassing crystallization during solidification. Every liquid, when cooled, has a thermodynamique driving force to crystallize, but this process takes time for atoms to arrange themselves. By cooling the molten alloy faster than this critical rate, the liquid’s disordered structure is ‘frozen’ into the solid state. The first amorphous alloy, Au₇₅Si₂₅, was produced by Pol Duwez’s team using a ‘gun technique’ to propel a molten droplet onto a cold copper substrate, achieving the necessary rapid quenching.
A significant challenge was the limitation to very thin ribbons or foils, as heat could not be extracted quickly enough from thicker sections. This dirigé to the development of Bulk Metallic Glasses (BMGs). BMGs are multi-component alloys (typically 3 or more elements) with large atomic size mismatches, which frustrates the crystallization process and dramatically lowers the required critical cooling rate, allowing for the casting of parts several centimeters thick. Unlike crystalline metals that deform plastically through dislocation motion, metallic glasses deform elastically to much higher strains. Once their elastic limit is exceeded, deformation localizes into narrow regions called shear bands, often leading to catastrophic failure with little to no overall ductility. This combination of extreme strength but limited toughness is a key area of ongoing research.
DISPONIBLE POUR DE NOUVEAUX DÉFIS
Ingénieur mécanique, chef de projet, ingénierie des procédés ou R&D
Disponible pour un nouveau défi dans un court délai.
Contactez-moi sur LinkedIn
Intégration électronique métal-plastique, Conception à coût réduit, BPF, Ergonomie, Appareils et consommables de volume moyen à élevé, Production allégée, Secteurs réglementés, CE et FDA, CAO, Solidworks, Lean Sigma Black Belt, ISO 13485 médical
Nous recherchons un nouveau sponsor
Votre entreprise ou institution est dans le domaine de la technique, de la science ou de la recherche ?
> envoyez-nous un message <
Recevez tous les nouveaux articles
Gratuit, pas de spam, email non distribué ni revendu
ou vous pouvez obtenir votre adhésion complète - gratuitement - pour accéder à tout le contenu restreint >ici<
(si la date est inconnue ou non pertinente, par exemple « mécanique des fluides », une estimation arrondie de son émergence notable est fournie)
Inventions, innovations et principes techniques connexes
{{titre}}
{% si extrait %}{{ excerpt | truncatewords : 55 }}
{% endif %}
