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| 选区激光熔化过程熔池缺陷的形成机理研究 |
| Study on Formation Mechanism of Molten Pool Defects during Selective Laser Melting Process |
| 投稿时间：2023-10-17 修订日期：2023-11-01 |
| DOI： |
| 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 |
| 基金项目:国家自然科学基金(12062016)资助项目. |
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| 中文摘要: |
| 采用三维高保真计算流体动力学模型，研究了镍基高温合金GH4169在SLM过程中的熔池流动和缺陷形成过程，揭示了剥蚀、球化等缺陷的形成机理。模拟结果表明：熔池的驱动力主要为马兰戈尼力和表面张力，马兰戈尼力促使熔池由内而外流动，而表面张力导致熔池由外向内流动。剥蚀现象一般出现在熔池附近，当剥蚀区域较小时，剥蚀呈周期性出现和消失。而当剥蚀区域较大时，少量的熔融液体无法填充大区域的剥蚀，导致表面质量退化。当熔池的长深比小于3.4时，在高温区（马兰戈尼力为主要驱动力）与低温区（表面张力为主要驱动力）的交界处更容易发生球化现象。研究成果有助于指导工艺优化提升选区激光熔化成形件的表面质量。 |
| 英文摘要: |
| 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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