Corrosive agent for displaying grain boundaries of high-damping manganese-based copper alloys and corrosion method thereof

Abstract

The invention relates to a corrosion method for displaying grain boundaries of high-damping manganese-based copper alloys. Metallographic corrosion is carried out for high-damping manganese-based copper alloys whose Mn content is higher than 70% and Cu content is higher than 20%, and a sample is prepared according to a conventional method; a saturated solution of picric acid and a nitric acid alcohol solution whose concentration is 5-15% are fully mixed according to a volume fraction ratio of 1 to 0.8-1 to 1.2, and the solutions are placed at a normal temperature for at least 10 minutes; a polishing surface of a sample is upward and placed in a corrosive agent, corrosion is carried out for at least 4 minutes, the corroded high-damping manganese-based copper alloy sample is taken out and washed with flowing water as well as washed with alcohol and dried, and etching is completed for displaying crystal boundaries; observation is carried out under a 100x microscope in order to obtain crystal grain displaying photographs, and a comparsion method or a grid method or a resection is used for carrying out determination of grains. The corrosive agent is used for corroding in order to obtain clear grain sizes, corrosion of matrix structures is avoided, and the problem that crystal boundary and twin crystal appear at the same time is solved; and the method has the advantages of simple operation, accurate determination, higher accuracy, and usage safety.

Description

technical field [0001] The invention relates to an etchant for displaying high-damping manganese-based copper alloy grain boundaries and a corrosion method thereof, belonging to the technical field of metallographic analysis. Background technique [0002] With the rapid development of modern industry, vibration and noise have become one of the outstanding problems and pollution hazards in engineering. Metal damping material is a kind of structure-function integrated material used to reduce vibration and noise. Using it to manufacture related vibration source components can effectively solve vibration and noise problems in machinery manufacturing and related engineering fields. [0003] Copper alloys with damping effect mainly include manganese-copper alloys, which belong to twin crystal alloy materials. The mechanism of its damping is: the alloy produces a large number of high-density twin substructures due to Neil transformation and martensitic phase transformation during ...

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Problems solved by technology

See Figure 9 As shown, after being corroded by saturated picric acid solution, the damping manganese-based copper alloy test block was observed at 100 times and the grain display photos were obtained. Although the grain boundaries can be observed carefully, the grain size cannot be judged intuitively and accurately.

The other is to use oxalic acid solution for electrolytic treatment to display the grain size of the damping manganese-based copper alloy, see Figure 10 As shown, after electrolytic corrosion with oxalic acid solution, the damped manganese-based copper alloy test block was observed at 100 times and the grain display photos were obtained. Although the grain boundaries can be clearly displayed, the continuity is not good, and a large number of twins appear, which will damage the grains. There is a lot of interference in grain assessment

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