Metallographic Sample Preparation Example

The metallographic sample preparation example shared this time is EN-AW-5083 aluminum alloy sample. The three samples sent by the customer are cut into 30mm*30mm cuboids by iqualitrol iCut-460Z automatic precision cutting machine, two each for hardness testing and electrolytic polishing corrosion.

The cut samples are chamfered.

1. Brinell Hardness Test

The surface of the sample used for hardness testing is directly ground with 2000# sandpaper. And the sample is measured using iqualitrol digital display low load Brinell hardness tester HBS-62.5.

2. Electrolytic Polishing and Corrosion

Another sample was quickly inlaid using iqualitrol light-curing inlay machine. It only takes 1 minute to complete the inlay of multiple samples at the same time, and then the DPF-2 electrolytic polishing and corrosion instrument was used for corrosion.

When inlaying and injecting liquid, pay attention to exposing the upper surface of the sample for subsequent electrolytic polishing and corrosion.

When preparing aluminum alloy samples, first grind the sample at a speed of 300r/min using 180#, 600#, 800#, and 1500# sandpaper in sequence. Then, at a speed of 500r/min, use gray velvet polishing cloth with 2.5μm and 1μm sprays to polish the sample, and finally use damping polishing cloth with silica final polishing liquid for final polishing.

After the sample is prepared, use an electrolytic polishing and corrosion instrument to corrode the sample for 15-20 seconds using 32% fluoroboric acid corrosion solution at a voltage of 20V. After the surface is blown dry, use a metallographic microscope to observe the metallographic structure of the sample at 100 times.

3. Observe under metallurgical microscope by model iMet-224