Method capable of reducing mixed crystal formation at section abrupt-change portion of single-crystal high-temperature alloy

Abstract

The invention relates to the field of metal material solidification control, in particular to a method capable of reducing mixed crystal formation at a section abrupt-change portion of a single-crystal high-temperature alloy. In an orientated growth process of the single-crystal high-temperature alloy, the section abrupt-change portion is easily super-cooled locally to form mixed crystal as a result of too quick heat dissipation. The method is characterized in that direct-current current is an oriented condensation process of a single-crystal high-temperature alloy casting, and the current forms segregation at the section abrupt-change portion by utilizing resistivity difference between a solid phase and a liquid phase as well as among melts of different temperatures, so that a part with arelatively low temperature generates more joule heat, and local super-cooling at the section abrupt-change portion is alleviated or eliminated, and therefore, mixed crystal nucleation and growth trend is reduced or eliminated. Direct-current current is applied in a single-crystal high-temperature alloy growth process to reduce formation of mixed crystal at the section abrupt-change portion, so that a single-crystal organization with good orientation consistency and a uniform and compact organization is obtained, and therefore, the problem that mixed crystal is liable to form at the section abrupt-change portion while a single-crystal high-temperature alloy component is cast at present is solved.

Description

technical field [0001] The invention relates to the field of solidification control of metal materials, in particular to a method for reducing the formation of miscellaneous crystals at sudden changes in cross-sections of single-crystal high-temperature alloys. Background technique [0002] Single crystal superalloy castings are the key components of advanced engines, and their structural integrity is an important prerequisite to ensure their high performance. However, for single crystal superalloy castings with abrupt cross-sections, local supercooling is easily formed at the edge of the abrupt cross-section during the directional solidification casting process due to rapid heat dissipation. When the supercooling meets the nucleation and growth conditions, the The growth of miscellaneous crystals occurs, which seriously reduces the performance of single crystal castings. In the current actual production, the macroscopic temperature field of single crystal growth can be wel...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for reducing the formation of miscellaneous crystals at the sudden change in the cross section of single crystal superalloy, to solve the current problem that miscellaneous crystals are easily formed at the sudden change in cross section when casting single crystal superalloy structural parts, and is suitable for preparing various Single crystal superalloy casting with sudden cross-section

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