MICROSTRUCTURE AND COMPRESSION PROPERTIES OF Fe-Cr-B ALLOY MANUFACTURED USING LASER METAL DEPOSITION

초록

Fe-Cr-B alloy is a material with precipitation of boride inside Fe matrix, and it features outstanding hardness and wear resistance properties. However, Fe-Cr-B alloy is a difficult material to process, making it difficult to use as a bulk type structure material which requires delicate shapes. This study attempted to manufacture Fe-Cr-B alloy using a 3D printing process, laser metal deposition. This study also investigated the microstructure, hardness and compression properties of the manufactured alloy. Phase analysis results is confirmed that alpha-Fe phase as matrix and (Cr, Fe)(2)B phase as reinforcement phase. In the case of (Cr, Fe)(2)B phase, differences were observed according to the sample location. While long, coarse, unidirectional needle-type boride phases (similar to 11 mu m thickness) were observed in the center area of the sample, relatively finer boride phases (similar to 6 mu m thickness) in random directions were observed in other areas. At room temperature compression test results confirmed that the sample had a compression strength is approximately 2.1 GPa, proving that the sample is a material with extremely high strength. Observation of the compression fracture surface identified intergranular fractures in areas with needle-type boride, and transgranular fractures in areas with random borides. Based on this results, this study also reviewed the deformation behavior of LMD Fe-Cr-B alloy in relation to its microstructures.

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