Atomistic modeling and experimental Studies in direct metal laser sintering

Abstract

Laser Additive Manufacturing has emerged as an advanced manufacturing newlinetechnique to fabricate components in a layered fashion by fusing the powder newlineparticles. This process is multifaceted and pivotal to understand the underlying newlinephysics of the coalescence of powder particles during the process, which impacts newlinethe structural and mechanical properties of the build component. The consolidation newlineof metal powders having nano-sized particles in direct metal laser sintering process newlinehas a profound effect on the crystal structure, mechanical, and physical properties newlineof the fabricated part. This research work mainly focuses on studying the effect of newlineprocess parameters (laser power and scan speed) on the coalescence behavior of newlineAlSi10Mg powders fabricated using direct metal laser sintering (DMLS). A newlineclassical molecular dynamics (MD) model is developed for the coalescence of prealloyed newlinealuminum alloy (AlSi10Mg) particles during the laser additive newlinemanufacturing process. The neck growth, shrinkage ratio, the radius of gyration, newlineand diffusivity are calculated with respect to the sintering time, which gives the newlinefundamental understanding of the sintering behavior of metal powders at the newlineatomistic level. The model is further employed to investigate the neck growth and newlinecoalescence kinetics of different pairs of particle size with changing the laser newlineenergy density from 7 to 17 J/mm2.The current study reveals that solid state and newlineliquid state diffusion takes place during the sintering of metal powders in the direct newlinemetal laser sintering process. newlineIn the experimental part, the structural and mechanical analyses were newlineperformed on AlSi10Mg fabricated using direct metal laser sintering process where newlinelaser power and scan speed were varied. X-ray diffraction (XRD) analysis was newlineperformed on the specimens and Mg2Si clusters were detected. Heat affected zone, newlinefine and coarse grain regions were observed using optical microscopy and field newlineemission scanning electron microscope. Increasing laser power at a fixed scan newlinespeed, the microstructure becomes