Grain refinement of alloys using magnetic field processing
AssigneeExxonMobil Research and Engineering Company
InventorsJayoung Koo, Shiun Ling, Michael John Luton, Hans Thomann, Narasimha-Rao Venkata Bangaru
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Abstract
A method for refining the grain size of alloys which undergo ferromagnetic to paramagnetic phase transformation and an alloy produced therefrom. By subjecting the alloy to a timed application of a strong magnetic field, the temperature of phase boundaries can be shifted enabling phase transformations at lower temperatures.
Claims22
A method for refining the grain size of an alloy which undergoes a magnetic field induced phase transformation, comprising:
- (a) subjecting the alloy to a uniform magnetic field of a sufficient strength and for a time sufficient to cause the alloy to transition from a first phase ratio to a second phase ratio;
- and
- (b) decreasing the uniform magnetic field to allow the alloy to transition from the second phase ratio to a third phase ratio, wherein the third phase ratio may be the same or different from the first phase ratio;
- and
- (c) repeating steps (a) and (b), to produce an alloy having equiaxial grain size of less than about 10 microns.
A method for refining the grain size of an alloy, comprising:
- a ferromagnetic phase and a paramagnetic phase separated by a phase boundary, comprising:
- (a) subjecting the alloy with a first volume ratio of the ferromagnetic phase and the paramagnetic phase, to a uniform magnetic field of sufficient strength to cause the temperature of the phase boundary to shift upwards, and a sufficient time to change the first volume ratio to a second volume ratio such that the uniform magnetic field causes at least about 15 vol % of the alloy to transform from the paramagnetic phase to the ferromagnetic phase;
- (b) decreasing the uniform magnetic field to allow the alloy to transition to a third volume ratio wherein the third volume ratio may be the same or different from the first volume ratio;
- and
- (c) repeating steps (a) and (b) to produce an alloy having equiaxial grain size of less than about 10 microns.
A method for refining the grain size of an alloy, comprising:
- a ferromagnetic phase and a paramagnetic phase separated by a mixed phase region having a lower phase boundary and an upper phase boundary, comprising:
- (a) subjecting the alloy with a first volume ratio of the ferromagnetic phase and the paramagnetic phase, to a uniform magnetic field of sufficient strength to cause the temperature of the phase boundary to shift upwards, and a sufficient time to change the first volume ratio to a second volume ratio such that the uniform magnetic field causes at least about 15 vol % of the alloy to transform from the paramagnetic phase to the ferromagnetic phase;
- (b) decreasing the uniform magnetic field to allow the alloy to transition to a third volume ratio wherein the third volume ratio may be the same or different from the first volume ratio;
- and
- (c) repeating steps (a) and (b) to produce an alloy having equlaxial grain size of less than about 10 microns.
Dependencies are inferred from the claim text.