Aluminum Alloys - Metallographic Sample Preparation

Aluminum alloys can be prepared for metallographic analysis using OnPoint Abrasives' consumables and procedures. Below is a step by step procedure for metallographic sample preparation that can be used on a wide range of aluminum alloys such as 6061, 5052, and 3003.

Sectioning: Section specimen with MultiSec abrasive blade or multi-purpose diamond blade.

Mounting: Compression mount specimen using PhenoMount phenolic powder. Phenolic mounting compounds are available in black, green, and red color. For samples that require castable mounting, we recommend using EpoPro liquid epoxy system.

Grinding and Polishing: In this section, we've provided two methods for preparing your specimen for analysis, Traditional Method and Advanced Method.

The Traditional Method uses a series of Silicon Carbide grinding papers to first planarize and grind the surface to around 3-5 micron (1200 grit), before moving to polishing steps using suspensions and cloths. This method is effective for general purpose metallography, although it can introduce some relief, or rounding of the specimen's edge.

*For the final step, alternate between the alumina and ProPrep colloidal silica at 20 second intervals. Finish with a large dose of alumina when 0:30 seconds remain. 

Note: Clean specimen by gently scrubbing the surface with a cotton ball under running water. Repeat until all alumina is removed. Use of an ultrasonic cleaner is highly recommended for samples with high porosity content or intricate geometries.

Our Advanced Method uses one or two steps of SiC grinding paper to initially planarize the mounted specimen. This is followed by a series of "loose" abrasive polishing steps that utilize diamond and alumina suspensions along with polishing cloths. The less aggressive nature of this method preserves the specimen's edge and produces ultra-flat results. This can be critical for analysis such as coating thickness measurements or samples that are examined near the specimen's edge. It is viewed by many that the "advanced" methods of preparation offer superior results and higher consistency when compared to traditional methods.

 *For the final step, alternate between the alumina and ProPrep colloidal silica at 20 second intervals. Finish with a large dose of alumina when 0:30 seconds remain. 

Note: Clean specimen by gently scrubbing the surface with a cotton ball under running water. Repeat until all alumina is removed. Use of an ultrasonic cleaner is highly recommended for samples with high porosity content or intricate geometries.