A heat treatment method for additively manufacturing single crystal nickel-based superalloys

Abstract

The invention relates to a heat treatment method for additive manufacturing monocrystal nickel-base superalloy. The heat treatment method includes the steps that to-be-processed additive manufacturingmonocrystal nickel-base superalloy is subjected to solid solution heat treatment, aging heat treatment and cooling in a heat treatment furnace, slicing and sample preparation are carried out on the processed additive manufacturing monocrystal nickel-base superalloy, combined with microstructure characterization and crystal orientation analysis, and the effect of the heat treatment method is judged according to the size of gamma<'> phase and whether recrystallization occurs in a heat-affected zone and a epitaxial growth zone or not. According to the heat treatment method for the additive manufacturing monocrystal nickel-base superalloy, the gamma<'> phase is dissolved, re-precipitated, and grown up in the subsequent aging process by applying appropriate heat energy to the additive manufacturing monocrystal nickel-base superalloy, thus the gamma<'> phase with uniform size distribution and regular shape is obtained, and the purposes of microstructure improvement and alloy property optimization are achieved.

Description

technical field [0001] The invention belongs to the field of metal heat treatment, and in particular relates to a heat treatment method for additively manufacturing single crystal superalloys. Background technique [0002] Nickel-based superalloys are the key hot-end component materials of modern aero-engines and gas turbines (such as turbine blades, turbine disks, combustion chambers, casings, etc.), and are the most widely used, largest-used, and highest-ranking components among various high-temperature components. A superalloy. Single crystal nickel-based superalloys avoid the adverse effects of grain boundaries on mechanical properties in high temperature environments, so the heat resistance of hot end parts made of single crystal superalloy materials is further improved. [0003] The hot-end parts of engines and gas turbines, especially high-pressure turbine working blades, which work for a long time under high temperature, harsh environment and complex stress state, t...

AI Technical Summary

Problems solved by technology

These heat treatment systems are formulated for as-cast nickel-based superalloys, but there are some problems for the additive manufacturing of single-crystal nickel-based superalloys, mainly because of the slow cooling rate of as-cast superalloys, thick dendrites, and composition segregation , The structure contains a large number of eutectics, and the stress level is low; and the additive manufacturing of single crystal nickel-based superalloys is due to its ultra-fast cooling rate (the cooling rate of the molten pool is 10 times higher than that of traditional castings. 2 ~10 3 times), leading to the refinement of dendrites, the reduction of composition segregation, and the suppression of eutectic precipitation in the structure, the morphology of the γ' phase is far from that of the as-cast state, and the residual stress level is relatively high

Therefore, it is inappropriate to continue to use the heat treatment system formulated for as-cast superalloys.

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