Investigation of laser scan strategy on tensile and microstructural characteristics of inconel 718 fabricated by DMLS process

Abstract

Metal additive manufacturing, mainly direct metal laser sintering (DMLS), is presiding over all the mechanical and manufacturing segments with its fascinating progress. Several studies have proved that the build orientation of the additive manufacturing (AM) process is very significant and influential on the mechanical properties. In this study, In718 samples were fabricated through DMLS with different Scan Orientation Strategies (SOS) of 670 (sample A), 670 + 900 (sample B), and 900 (sample C), and their impacts on mechanical characteristics and microstructures were discussed. The study revealed that due to a higher rate of elemental segregation, sample B exhibited a UTS of 1231 Mpa, which is approximately 17.21% greater than sample C and 8.36% greater than sample A. In the same way, the percentage elongation of sample C is 21% greater than that of sample B and 10.5% superior to sample A. Images obtained using a scanning electron microscope (SEM) and an optical microscope (OM) were analysed to support the specimens' fractographies, columnar pattern growth, and elemental segregation. The fractured surfaces of tensile samples A & C revealed uniform fracture and equiaxed failures with deep dimples, whereas the fractured surface of sample B revealed the presence of an intermetallic configuration displaying brittle and low plastic deformation.