|Study on Formation Mechanism of Molten Pool Defects during Selective Laser Melting Process
|中文关键词: 选区激光熔化 计算流体动力学 镍基高温合金 熔池缺陷 表面质量
|英文关键词:Selective laser melting Computational fluid dynamics Nickel-based superalloy Molten pool defect Surface quality
| 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 from the inside out, while surface tension causes the melt pool to flow from the outside in. 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 less 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.
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