Accession Number : AD0716228

Title :   The Structural Features of Undercooled Nickel and Nickel-Oxygen Alloys,

Corporate Author : DEFENCE STANDARDS LABS MARIBYRNONG (AUSTRALIA)

Personal Author(s) : Jones,B. L. ; Weston,G. M.

Report Date : 06 SEP 1970

Pagination or Media Count : 6

Abstract : A series of nickel ingots having oxygen contents ranging between 22 and 540 ppm have been undercooled by amounts up to 271 degC to examine the separate effects of oxygen and undercooling on grain structure. In nickel containing more than 100 ppm oxygen, undercooling by more than 100 degC produces a uniform very fine grain structure (<0.2 mm dia.), by a dendrite arm remelting process. Ingots containing less than 100 ppm oxygen undercooled by less than 160 degC had very coarse dendritic structures, but undercooling by more than 160 degC caused grain refinement to (0.6-0.9 mm) by a recrystallization process. This recrystallization is believed to be associated with the inhibition of recovery processes by interstitial solute impurities. (Author)

Descriptors :   (*NICKEL, GRAIN STRUCTURES(METALLURGY)), (*NICKEL ALLOYS, GRAIN STRUCTURES(METALLURGY)), COOLING, GRAIN SIZE, DENDRITIC STRUCTURE, RECRYSTALLIZATION, AUSTRALIA

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE