Study on formation mechanism of molten pool defects during selective laser melting process
Received:October 17, 2023  Revised:November 01, 2023
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DOI:10.7511/jslx20231017001
KeyWord:selective laser melting  domputational fluid dynamics  nickel-based superalloy  molten pool defect  surface quality
              
AuthorInstitution
周翔 南昌航空大学 航空制造工程学院, 南昌
江五贵 南昌航空大学 航空制造工程学院, 南昌
李琦 南昌航空大学 航空制造工程学院, 南昌
陈韬 南昌航空大学 航空制造工程学院, 南昌
彭杰 南昌航空大学 航空制造工程学院, 南昌
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Abstract:
      A three-dimensional high fidelity computational fluid dynamics model was used to study the melt flow and defect formation process of nickel-based high-temperature alloy GH4169 during SLM,revealing the formation mechanisms of molten pool defects such as denudation and balling during the SLM process.The simulation results indicated that the primary driving forces governing the molten pool are the Marangoni force and surface tension,where the Marangoni force causes the melt pool to flow out from the inside,while surface tension causes the melt pool to flow inwards from the outside.Denudation phenomena usually occur near the molten pool.When the denudation area is small,it appears and disappears periodically.However,when the denudation area is large,a limited amount of molten liquid cannot sufficiently fill the large denudation area,resulting in surface quality degradation.Furthermore,when the length-to-depth ratio of the melt pool is lower than 3.4,balling is more likely to occur at the interface between the high-temperature region dominated by Marangoni force and the low-temperature region dominated by surface tension.The present work contributes to guiding process optimization and improving the surface quality of SLM parts.