Aluminum and its alloys have a low density, excellent plasticity, high conductivity, thermal conductivity, and corrosion resistance, as well as excellent casting and cutting forming properties. An important aspect of metallographic inspection of aluminum alloys is to inspect the poor microstructure formed during the processing of aluminum alloys, such as needle like eutectic silicon in cast aluminum silicon alloys, pinholes and various macroscopic defects in cast aluminum alloys, machining defects in processed aluminum alloys, and overheating and overburning microstructure generated during the heat treatment process of cast and deformed aluminum alloys. QMAXIS provides the following plan for the preparation of metallographic samples of aluminum alloys for your reference.

After being eroded by a 10g NaOH+100ml H2O solution, at a magnification of 90X
Microstructural photos of aluminum alloy AA7075 under polarized light

    The specific preparation steps for aluminum alloy samples are as follows:

    Cutting: QMAXIS metallographic cutting machine, with grinding wheel blades selected for cutting non ferrous metal materials

    Embedding: Hot press inlay machine, using QMAXIS black phenolic resin powder as the inlay material

    Mechanical sample preparation: Metpol-A

    Note: Comp. refers to the rotation of the sample fixture and the grinding disc in the same direction, Contra refers to the reverse rotation of the sample fixture and the grinding disc

    Etching: Etch with a solution of 10g NaOH+100ml H2O

    Attention: When polishing with diamond polishing paste/liquid, add QMAXIS DiaFluid water-based polishing lubricant as a lubricant and dispersant. After each polishing step, it is necessary to clean with alcohol or distilled water and dry the sample with compressed air. After the nitric acid alcohol solution corrodes, the sample needs to be washed clean with distilled water first, then cleaned with anhydrous alcohol, and dried with compressed air or a hair dryer.

    Can the above preparation methods help you solve the sample preparation problem? For more technical guidance, please contact QMAXIS customer service or application engineers.