Directional recrystallisation in Inconel MA 6000 nickel base oxide dispersion strengthened superalloy
作者:
BalochM. M.,
BhadeshiaH. K. D. H.,
期刊:
Materials Science and Technology
(Taylor Available online 1990)
卷期:
Volume 6,
issue 12
页码: 1236-1246
ISSN:0267-0836
年代: 1990
DOI:10.1179/mst.1990.6.12.1236
出版商: Taylor&Francis
数据来源: Taylor
摘要:
AbstractThe directional recrystallisation process which leads to the growth of highly anisotropic‘new’grains in an oxide dispersion strengthened nickel base superalloy is investigated to elucidate the mechanism of recrystallisation and the process variables important in controlling microstructural evolution. It is found that after extrusion and hot deformation, the alloy consists of an ultra fine equiaxed grain microstructure characteristic of a material which has undergone dynamic primary recrystallisation. Thus, the directional recrystallisation which follows when the hot rolled sample is annealed in a moving temperature gradient (zone annealed) is really a secondary recrystallisation phenomenon. By comparing grain boundary mobility with the rate of zone annealing, it was theoretically predicted and experimentally observed that directional recrystallisation should give way to equiaxial recrystallisation when the interface velocity is less than the speed of zone annealing. The variables involved in the anisothermal zone annealing process appear to rationalise when the effects of temperature and time are consolidated into a single parameter, the kinetic strength of the heat treatment. Directional recrystallisation is found to occur only when a critical value of the kinetic strength is exceeded, irrespective of the peak temperature or traverse speed during zone annealing.MST/1268
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