Work

In-situ synchrotron X-ray diffraction study of microstructure and strain evolution in brazed stainless steel joints under tensile loading

Year: 2026

Type: article

Abstract: Brazed stainless steel joints are critical in heat exchanger applications but often suffer from residual stresses and brittle intermetallics. Using in-situ synchrotron X-ray diffraction and fluorescence at the DanMAX beamline, we investigated Fe-based filler joints in SS316 under tensile loading. Elemental mapping and phase analysis revealed distinct interfacial solidification zones (ISZ), athermal solidification zones (ASZ), and diffusion-affected zones (DAZ), with a pronounced microstructural asymmetry observed particularly within the diffusion-affected region due to the uneven thermal gradient during brazing. Strain tensor mapping showed strong elastic anisotropy and stress localization at boride-rich zones, directly correlating with the observed fracture path. The results demonstrate the capability of synchrotron-based analysis to provide comprehensive insight into the interplay between chemical composition, microstructure, and stress in governing joint integrity, thereby informing strategies for improving toughness through process optimization.

Source: Materials & Design

DOI: 10.1016/j.matdes.2026.116053