Class 6 materials include titanium, Inconel, nickel-based superalloys, and cobalt alloys—recognized for their strength, corrosion resistance, and performance in extreme environments. These alloys are used in aerospace, energy, medical implants, and advanced manufacturing. Metallographic preparation is typically routine but benefits from controlled polishing to maintain phase contrast and minimize surface oxidation.
Reactive metals like titanium can oxidize quickly, especially during grinding or prolonged polishing.
Revealing microstructure in Ni-based and Ti alloys may require tailored etchants and timing precision.
Fine precipitates and dual-phase structures require careful prep to highlight morphology without overpolishing.
Polishing may introduce topographical relief between matrix and intermetallics, requiring cloth and pressure adjustment.
Use low-speed diamond saws with coolant to minimize heat and oxidation. Avoid thermal damage near edges.
Compression or castable mounting works well. Orientation may help expose grain structure or phase boundaries.
Start with SiC or alumina abrasives. Use moderate force and rinse thoroughly to reduce oxidation buildup.
Use diamond suspension followed by colloidal silica. Adjust cloth type to reduce relief and maintain contrast.
Microstructure appears free of polishing relief
Distinct phases visible with minimal overetching
Oxidation artifacts are absent across the field
Gamma prime or alpha-beta regions are clear