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Go to Editorial ManagerFunctionally graded materials were created using laser-directed energy deposition technology. This work examines how different mixing ratios of Stainless Steel 316L and Inconel 625 affect the relative density and porosity of these materials. Twelve samples were created using a constant laser power of 600 W, three different laser scan speeds (20, 25, and 30 mm/s), and four different SS316L/IN625 transition ratios (85%/15%, 60%/40%, 40%/60%, and 15%/85%). To determine the volumetric distribution across the compositional gradients, the porosity and relative density measurements were taken. Optical and scanning electron microscopy were used for microstructural analytical characterization to differentiate between compositional gradients in grain shape and phase distribution. The mechanical performance was examined using microhardness measures, namely the Vickers method. This study applied to prove the process parameters and compositional transformations to the resulting microstructural features and mechanical properties, providing insight into optimizing the laser-directed energy deposition-manufactured functionally graded materials for advanced performance. The best graded composition was found that gives the best overall performance based on experimental data.
Liquid nitrate is an important method used to improve mechanical properties. One of these properties is resistance to fatigue. The aim of this study was to improve the fatigue resistance of the stainless steel 316L. The rotational bending method was used with constant and variable stresses at different times of (1, 3, 5) hours and at (530, 630) C0. These tests were performed before and after nitration._x000D_ The results showed that the depth of the nitride layer was (0.21, 0.33, 0.45) mm, increasing with time nitriding when the temperature was 530 C0. While the depth of this layer at a temperature of 630 C0 (0.26, 0.39,0.5) mm with increasing time. As a result of these processes, a layer of solid chromium nitrides and other phases of iron nitride were formed on the outer surface. These layers helped to inhibit the growth of the cracks and their progress in addition to the generation of pressure stresses on the surface leading to obstructing the progress of the cracks._x000D_ This study showed that the fatigue resistance was directly proportional to the increase in nitrate time due to the increased depth of the hardened layer, but this resistance decreased when the temperature was 630 C0 due to the formation of brittle phase with low resistance.