Metallographic corrosion method and metallographic corrosive agent for aluminum alloy

Abstract

The invention discloses an aluminum alloy metallographic corrosion method and a metallographic corrosive agent thereof. The metallographic corrosion method comprises the following steps that a, a 7055 aluminum alloy sample is subjected to pre-cleaning, hot inlaying, mechanical grinding and mechanical polishing treatment, washed with clear water and blow-dried, and then a metallographic sample is obtained; b, sequentially adding nitric acid, hydrochloric acid, sulfuric acid, hydrofluoric acid and deionized water into a container, and mixing to obtain a metallographic corrosive agent, wherein the metallographic corrosive agent comprises the following components in percentage by volume: 4-5% of nitric acid, 2-3% of hydrochloric acid, 1.5-2.5% of sulfuric acid, 2.5-3.5% of hydrofluoric acid and the balance of deionized water; and c, pouring the metallographic corrosive into a culture dish, placing the culture dish in a constant-temperature environment of 22-28 DEG C, immersing the metallographic sample into the metallographic corrosive, corroding for 25-35 seconds, taking out, washing, drying, and observing. The corrosion method is simple, the corrosion time is short, the effect of the metallographic corrosive agent is fully exerted, and the crystal boundary and crystal grains of the 7055 aluminum alloy are clearly displayed.

Description

technical field [0001] The invention relates to metal materials, in particular to a method for metallographic corrosion of 7055 aluminum alloy and a metallographic corrosion agent thereof. Background technique [0002] 7055 aluminum alloy belongs to the Al-Zn-Mg-Cu series (7XXX series) aluminum alloy, and is the best representative of this series of aluminum alloys. Al-Zn-Mg-Cu series aluminum alloy is also called ultra-high-strength aluminum alloy because of its extremely high strength. It is also called super hard aluminum in China. It is developed on the basis of Al-Zn-Mg series aluminum alloy. came. The alloy element composition of the 7055 aluminum alloy sample includes: 0wt%-0.10wt% Si, 0wt%-0.15wt% Fe, 2.0wt%-2.6wt% Cu, 0wt%-0.05wt% Mn, 1.8wt% -2.3wt% Mg, 0wt%-0.04wt% Cr, 7.6wt%-8.4wt% Zn, 0wt%-0.06wt% Ti, 0.08wt%-0.25wt% Zr, balance Al. 7055 aluminum alloy has extremely high strength, good toughness and good stress corrosion resistance. Based on its excellent perf...

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Problems solved by technology

7055 aluminum alloy has extremely high strength, good toughness and good stress corrosion resistance. Based on its excellent performance, in recent years, a new generation of 7055 with higher strength, better toughness and better corrosion resistance is being vigorously developed at home and abroad. And 7x55 aluminum alloy, among which there are many studies on optimizing alloy composition, improving alloy structure and developing new heat treatment system, so it is necessary to compare the metallographic structure of 7055 aluminum alloy under different treatment methods and then study its performance, but The metallographic structure of this series of aluminum alloys is difficult to corrode. Even if it is corroded, the structure is often incomplete or unclear. Therefore, it is very necessary to prepare a corrosion solution that can corrode the metallographic structure of this alloy.

The anodic coating corrosion method is costly, time-consuming, and inefficient, which will greatly prolong the time for metallographic sample preparation

And for film-coated samples, the colors are usually brighter at low magnifications. For example, 50x and 100x have the best effect, but the effect of 200x is not good. The thicker the film is, the clarity of the picture and the color of the picture are not ideal.

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