Method for preparing Al-Si-Cu-based alloy metallographic sample and displaying tissue thereof

Abstract

Preparation of Al-Si-Cu alloy metallography sample and display organize method, it includes the following steps: a. rough grinding: using size reduction water sandpapers in turn, the samples are accomplished at least two times water polished, and after each sandpaper changing rotate 90 degree, until eliminating the scratch of the previous process, and before sandpaper changing, the samples are cleaned with water; b. electrolytic polishing: using the electrolytic polishing machine, polish at least two times, and after each time, rinse and cool with water; c. flannel polishing: samples polish on the single direction with the polishing pasted silk cloth; d. chemical etching: the etchant is dropped on the sample surface, eroded using wipe-mop method. Compared with the existing technologies, the advantages of the invention is to take electrolytic polishing and flannel polishing at the same time, combining chemical corrosion, optimized selecting the etchant of HF:HCl:H2O=2:3:18, to successful prepare metallographic examination samples. It is a high efficiency for sample preparation, low labor intensity, and it is the technology to obtain a very clear and integrity crystal boundary.

Description

technical field [0001] The invention belongs to the technical field of metallographic sample preparation, and in particular provides a method for preparing an aluminum-silicon-copper alloy metallographic sample and a method for displaying the structure. Background technique [0002] Due to the low hardness of 99.999% high-purity aluminum, pure aluminum and some aluminum alloys are very soft. When preparing metallographic samples, it is easy to scratch the surface during grinding and polishing, and it is difficult to obtain a very bright metallographic sample. It is more difficult to display the grain boundary of high-purity aluminum than that of ordinary aluminum. After corroding a sample with a dull surface, it will be difficult to completely display the grain boundaries, or even distinguish the grain boundaries, and it is difficult to measure the average grain size of the sample; and under low pressure, aluminum will deform, that is, after polishing Surface flow and defor...

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Problems solved by technology

[0002] Due to the low hardness of 99.999% high-purity aluminum, pure aluminum and some aluminum alloys are very soft. When preparing metallographic samples, it is easy to scratch the surface during grinding and polishing, and it is difficult to obtain a very bright metallographic sample. samples, and the high-purity aluminum grain boundary display is more difficult than the ordinary aluminum grain boundary display

After corroding a sample with a dull surface, it will be difficult to completely display the grain boundaries, or even distinguish the grain boundaries, and it is difficult to measure the average grain size of the sample; and under low pressure, aluminum will deform, that is, after polishing Surface flow and deformation are prone to occur during polishing and polishing. These deformed surfaces can mask the real microstructure and create false images, which prevent people from performing correct microscopic analysis of the sample.

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