2026 Hong Ni Superalloy Etching Methods

Gamma prime (γ ′) precipitates and grain boundary (GB) carbides govern the high-temperature performance of Ni-based superalloys, and their reliable quantification is essential for microstructural evaluation and alloy development. However, conventional etching procedures are often transferred between alloys without considering composition-dependent changes in γ ′ size and fraction or carbide population, which can cause unstable contrast, γ-matrix damage, and unreliable image-based interpretation. Here, we establish composition-tailored etching conditions for Haynes® 282 (γ ′ ~23 nm) and two model alloys with modified Al–Ti and Nb–Ta contents, and evaluate their suitability for phase-selective Scanning electron microscopy (SEM) imaging. After identical mechanical treatment of these samples, we characterized the morphological features and phase distributions, determining the effectiveness of our tailored etching approach versus traditional methods. Results indicate significant improvements in image clarity and reliability, thereby enabling more precise assessment of microstructural details essential for alloy optimization and performance predictions. This research contributes to advancing methodologies in materials characterization, particularly in the context of high-performance nickel-based superalloys.