Effect of crystallographic texture and grain orientation on tribological properties of WAAM deposited IN625 alloy in weaving deposition strategy

Abstract

Understanding the variation in the local microstructure and texture of the as-built fabricated by wire arc additive manufacturing (WAAM) is highly challenging. They affect the mechanical and tribological properties of the builds. The deposition patterns and the process parameters are key factors that determine the microstructures and hence other properties. In the present study, builds of Inconel 625 alloy have been manufactured through WAAM by using a weaving pattern. The microstructure and their texture at the different locations of the deposited build have been investigated through electron backscattered diffraction (EBSD) and optical microscopy. The detailed evolution mechanisms of the micro-structure of the build have been studied followed by the quantitative analysis of the grain size, misorientation angles, fraction of recrystallized and deformed grains, and textures. Later the effect of texture components on the hardness, elastic modulus, and coefficient of friction (COF) of the build has been studied by using nano-indetation and nano-scratch tests. The grain size was found to be 33 μm, 110 μm, and 66 μm at the bottom, middle, and top, respectively. The top region was dominated by Cube {001}<uvw>, Goss {011}<100>, and E {111}<110> orientations, which changed to deformed texture Brass {110}<112> and Goss {011}<100> orientations in the middle region and cube texture at the bottom. Hardness was highest at the top region 5.33 GPa, followed by 4.02 GPa in the middle region and 4.74 GPa at the bottom. The COF was highest in the middle region at 0.456, which reduced to 0.323 in the bottom region. Sheared textured grains {111}<uvw> have shown greater value of COF and hardness than the {101}< uvw> and {100}<uvw> texture grains. The study has been carried out to investigate the variation in local mechanical properties due to microstructural variations. It will help industries to design components with homogeneous mechanical properties.