A Quantitative Characterization Method of Single Crystal Alloy Rafting Based on Digital Image Algorithm

Abstract

The invention belongs to the technical field of testing and characterization of the microstructure state of materials, and in particular relates to a method for quantifying the rafting of single crystal alloys based on digital image algorithms, comprising the following steps: 1) preparing metallographic samples of single crystal alloys after rafting, obtaining Alloy microscopic SEM image and converted into grayscale image; 2) Alloy microscopic SEM grayscale image binarization; 3) Binarized alloy microscopic SEM image cross-correlation calculation and microstructure parameter extraction; 4) Cross-correlation spatial distribution main Composition analysis; 5) Quantitative characterization of rafted state of single crystal alloy. The invention greatly reduces the cost and error of the manual statistical method, can quantify and characterize the changes of single-crystal alloy rafting morphology and size parameters, and has good engineering popularization.

Description

technical field [0001] The invention belongs to the technical field of testing and characterization of the microstructure state of materials, and in particular relates to a single crystal alloy rafting quantitative characterization method based on a digital image algorithm. Background technique [0002] Single crystal nickel-based superalloys are the preferred materials for the manufacture of aeroengine turbine blades due to their advantages of high temperature, high strength and good structural stability. However, turbine blades work in high-speed, high-pressure and high-temperature gas corrosion environments, and the strengthening phases inside the alloy will inevitably connect and coarsen under the action of high temperature, stress and time, forming a raft structure similar to bamboo joints, called It's called rafting. The high-temperature mechanical properties of single crystal nickel-based superalloys have a strong dependence on the morphology and shape of the interna...

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Problems solved by technology

[0003] In order to ensure the safe operation of the engine, it is necessary to have an enhanced rafting determination method for turbine blades in service in engineering. However, the existing rafting characterization methods are all based on the qualitative determination of alloy SEM images, and lack the rafting quantification that can be characterized. Measure to judge

[0004] Chinese patent CN 110411851 A discloses a method for characterizing the rafting degree of directionally solidified nickel-based superalloys based on the dimensionless ratio of transverse and longitudinal intersecting points of strengthening phases in SEM images of test strings and alloys, but this method can only reflect the morphology of alloy strengthening phases The change of the strengthening phase cannot reflect the change of the size of the strengthening phase

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