Effect of Solution Temperature on the Microstructure of 18%Ni Maraging Steel Modified With Nb—X‐Ray Diffraction and Electron Backscattered Scanning Diffraction ( <scp>EBSD</scp> ) Analyzes

ABSTRACT Maraging steels are high strength alloys used in applications that require both high mechanical strength and toughness. To achieve these properties, one of the heat treatments applied is solution treatment, although it can reduce toughness. This study compares the effect of two solution treatment temperatures, 910°C and 1100°C, on the microstructure and mechanical properties of a niobium‐containing maraging steel. Microstructural analysis was performed using X‐ray diffraction (XRD), electron backscatter diffraction (EBSD), light optical microscopy (LOM), and scanning electron microscopy (SEM). XRD analysis showed that dislocation density was higher for the sample treated at 1100°C. The XRD data were analyzed using the Williamson‐Hall method to estimate dislocation densities, and the Scherrer equation was applied to calculate crystallite sizes. EBSD revealed that solution treatment at 1100°C resulted in larger grain sizes and greater dissolution of Mo, Nb‐rich precipitates. Vickers hardness and Charpy impact tests were used to evaluate the mechanical properties. The Vickers hardness was slightly higher for the sample treated at 910°C due to the higher amount of precipitates present. In contrast, Charpy toughness increased with solution treatment temperature, reaching 98 J for the 1100°C condition, indicating greater impact energy absorption. Fractography showed predominantly ductile fractures in both conditions.