CONTROLE DE LA MICROSTRUCTURE DES ALLIAGES

A columnar grain structure and improved high temperature, high mechanical strength properties are provided in a metal article by solid state method. First the article is formed in a manner which places the metal microstructure in a condition of dislocation density which results in the metal microstr...

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Bibliographische Detailangaben
Hauptverfasser:	R.E. ALLEN, C.D. CALHOUN
Format:	Patent
Sprache:	fre
Schlagworte:	AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE APPARATUS THEREFOR CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS ANDNON-FERROUS ALLOYS CHEMISTRY CRYSTAL GROWTH FERROUS OR NON-FERROUS ALLOYS GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS METALLURGY METALLURGY OF IRON MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE REFINING BY ZONE-MELTING OF MATERIAL SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE SINGLE-CRYSTAL-GROWTH TREATMENT OF ALLOYS OR NON-FERROUS METALS UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL
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Beschreibung
Zusammenfassung:	A columnar grain structure and improved high temperature, high mechanical strength properties are provided in a metal article by solid state method. First the article is formed in a manner which places the metal microstructure in a condition of dislocation density which results in the metal microstructure undergoing relatively rapid transformation to relatively large grains when heated in the range of about 50 to less than 100 percent of the metal incipient melting temperature in degrees Rankine. Then the article so preconditioned is progressively and selectively heated in that temperature range but below the incipient melting temperature of the metal. This is accomplished by heating the article in a narrow zone. Such zone traverses the article, as a result of relative movement between the article and the source of heat energy, from the cooler portion and in the direction desired for growth of the principle axis of the columnar grains, with the zone having a thermal gradient of at least about 500 DEG F/in. A preferred form of a processed wrought article is characterized by grains of at least about 2000 microns in diameter and a length to diameter ratio of at least about 10.