Picture of the month - September 2025

This micrograph was imaged at the CMTC as part of an ongoing investigation into carbide–binder interactions in hardmetal systems in collaboration of TU Wien, Austria. The nearly spherical NbC grains resemble delicate snow bubbles frozen within the metallic matrix, evoking an abstract winter landscape at the microscale.
Typically, NbC grains exhibit a pyramidal morphology, but with increasing Fe content, they evolve into rounded forms—an evolution that opens the door to interpreting the grain growth mechanism through the classical LSW (Lifshitz–Slyozov–Wagner) theory.
Metallographic preparation of hardmetals is notoriously challenging due to the strong hardness contrast between phases and the near absence of color contrast under electron microscopy. This image also serves as an example of near-perfect metallographic preparation for such complex materials.

G M Sadrul Islam is in second year of PhD in the PM team. His PhD work is on “Effects of Binder Chemistry on Microstructure and Properties of Alternative Hardmetals”. This photo was taken in collaboration with Aurel DVORAK (TUW) and Veniamin Kuznetsov (TUW).