Microstructure and Texture Evolution of Hastelloy X and CeO2-Hastelloy X Composite Fabricated by Selective Laser Melting

This study investigated the microstructure and texture evolution of HX (Hastelloy X), HX-C (CeO₂ doped), and HX-W (wrought) alloys fabricated using selective laser melting (SLM). HX and HX-C samples exhibited a finer grain structure (10–25 μm and 5–15 μm, respectively) compared to HX-W (20–50 μm) in the XY plane (normal to the building direction) with dominant \(\:\left(100\right)\) grain orientation and significant elongation in the XZ plane (parallel to the building direction). The presence of low-angle grain boundaries (LAGBs) was higher in HX (60.7%) and HX-C (64.9%) compared to HX-W (1.4%), indicating higher internal energy and stored energy within the grains. The orientation distribution function (ODF) analysis revealed similar texture patterns in HX and HX-C samples for both XY and XZ planes, suggesting minimal influence of cerium oxide on texture development. Pole figure analysis confirmed a strong \(\:<110>\) fiber texture for HX and HX-C, further suggesting minimal impact on texture from cerium addition. Conversely, HX-W displayed a mixed grain orientation with reduced LAGBs and a distinct texture, indicating a more advanced recrystallization state. These findings suggest that cerium oxide addition refines the grain structure and enhances specific grain orientation while minimally affecting the overall texture development during SLM processing.

Graphical Abstract