Investigation of Frictional Deformation on Mechanical and Metallurgical Properties of Ni-based Functionally Graded Materials Developed by Wire and Arc Additive Manufacturing

The Ni-Cr-Mo-based functionally graded materials (FGMs) are widely used in defense, aerospace, and nuclear applications. In this study, Ni-Cr-Mo-based FGM is developed by using wire and arc additive manufacturing (WAAM) technique. The impact of compositional variations and post-deposition friction stir processing on metallurgical and mechanical properties are investigated. The WAAM-deposited sample exhibited a combination of dendritic and columnar grains, whereas post-deposition processed samples show refined recrystallized grains. The microhardness exhibited a gradual ascent, rising from 147 to 335 HV as moved from the bottom to the top of the samples under both conditions. This increase in microhardness trend can be attributed to the presence of CrNi₃ and MoNi₄ precipitates, as revealed in x-ray diffraction pattern analysis. The tensile test result also shows a continuous increase in strength from bottom to top of the samples in both, as-deposited and processed one.