Accession Number : AD0669250

Title :   RELATIONSHIP BETWEEN SEGREGATION SUBSTRUCTURES AND CASTING STRUCTURES.

Descriptive Note : Technical rept.,

Corporate Author : COMISION NACIONAL DE ENERGIA ATOMICA BUENOS AIRES (ARGENTINA) DEPARTAMENTO DE METALURGIA

Personal Author(s) : Biloni,H. ; Audero,M. A. ; Morando,R. ; Kiss,F. J. ; DiBella,R.

Report Date : MAR 1968

Pagination or Media Count : 78

Abstract : Contents: (1) Cellular solidification in HCP alloys of Zn-Cd grown unidirectionally. Node mechanism in substructure evolution and morphological features of dendritic stages emphasized. (2) Predentritic solidification, especial attention to columnar and equiaxed grains in Al-Cu alloys and Sn-Zn alloys. Also tridimensional model analysis used. (3) Studies of surface and subsurface structure of Al-Cu alloys, effects of mold, mold surface treatment (lamp black, graphite, copper). High heat extraction condition - copious nucleation is responsible for chill zone. Low heat extraction - coarse grain structure with dendritic morphology, size relates to convection. (4) Scale-up-of-ingot-size effects and magnetic field effects - in large sizes (500 - 5000 cc) poured in magnetic field coarse equiaxed region persists at center. Probable mechanism Winegard Chalmers. (5) Segregation substructures: origin and nature of chill zone; stability of crystal growing freely in bulk liquid; picture and degree of segregation in columnar region as function of alloy crystallography; grain boundary migration during cooling after solidification completed. (Author)

Descriptors :   (*CRYSTAL SUBSTRUCTURE, CASTINGS), (*CASTINGS, FREEZING), ZINC ALLOYS, CADMIUM ALLOYS, CRYSTAL GROWTH, POROSITY, SUPERCOOLING, GRAIN STRUCTURES(METALLURGY), ALUMINUM ALLOYS, COPPER ALLOYS, MICROSTRUCTURE, GRAIN BOUNDARIES, MAGNETIC FIELDS, THERMAL ANALYSIS

Subject Categories : Properties of Metals and Alloys
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE