Thermal behavior of the molten pool, microstructural evolution, and tribological performance during selective laser melting of TiC/316L stainless steel nanocomposites: Experimental and simulation…
By B. AlMangour, Dariusz Grzesiak, Jinquan Cheng, Y. N. Ertas. Journal of Materials Processing Technology, 2018
186 citations recorded by the source corpus.
Abstract Bulk-form nanocomposites of TiC-reinforced 316L stainless steel matrix were fabricated by selective laser melting (SLM), an emerging powder-bed additive manufacturing technique which allows the direct fabrication of usable end-products, using various volumetric laser energy densities (η). The microstructural features of the distribution and sizes of TiC nanoparticles, as well as the grain sizes and tribological performances of the SLM-processed nanocomposite parts, were sensitive to the applied η. Increasing η enhanced the dispersion state of nanoscale TiC owing to intensified Marangoni flow and the corresponding capillary force, which prevented TiC aggregation and promoted a uniform dispersion of reinforcements in the solidified matrix. However, with increasing η, the TiC particle size also increased, and some nanoparticles lost their initial nanostructure because of significant thermal accumulation within the molten pool. Increasing η also caused increases in the grain sizes of the fabricated nanocomposite because of the decreasing cooling rate. A simulation model was developed to enhance understanding of the manufacturability of these new materials, as well as to predict the temperature evolution and thermal behaviors of the molten pool under various η. The simulation modeled the effects of various η values on the temperature distribution evolutions and the corresponding effects of Marangoni convection during the SLM process. The temperature distribution was significantly influenced by the applied η; the maximum temperature gradient within the molten pool was increased significantly with increased η. The simulation results validated the experimental results and the underlying physical mechanism of the molten pool. The microhardness of the SLM nanocomposite decreased sharply with increased grain size due to the lower cooling rate, but increased with further increases in η because of the enhanced densification degree. Nanocomposites processed under the optimum condition of η = 200 J/mm3 showed the lowest wear rates accompanied by the formation of adherent and strain-hardened tribolayers on the worn surfaces of the nanocomposites, suggesting improved tribological performance.
Subfields: Automotive Engineering, Mechanical Engineering
View Paper: https://www.semanticscholar.org/paper/5ac9399d81a6a6cac253bbca244c3d40d805684a
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Citations in the corpus
- Material-structure-performance integrated laser-metal additive manufacturing (2021, background): “Critical energy densities need to be tailored to balance the competition between densification activity and grain coarsening, simultaneously achieving full density, grain refinement, and elevated printability (154, 155).”