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| 基板温度对激光增材制造熔池特征影响的数值模拟研究 |
| Numerical study of influence of substrate temperature on melt pool behavior in laser additive manufacturing |
| 投稿时间：2024-07-01 修订日期：2024-08-08 |
| DOI： |
| 中文关键词: 激光粉末床熔融 流体动力学 熔池 温度梯度 |
| 英文关键词:laser powder bed fusion fluid dynamics melt pool temperature gradient |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| 中文摘要: |
| 激光粉末床熔融增材制造技术具备成形自由度高和制造周期短等优势，在航空航天、生物医疗领域复杂结构一体化成形中展现出卓越潜力。激光粉末床熔融工艺涉及极高的升温、冷却速率和极强的温度梯度，不可避免地在构件内产生热应力和残余应力，严重损害构件的力学性能。因此，选取合理的工艺参数，降低熔池区域温度梯度幅值，对提高成型件质量有着重要的意义。本文基于流体动力学方法，使用多相流方法追踪粉末形状变化，考虑了反冲压力和马兰戈尼效应，计算分析了熔池流动行为和基板温度对温度梯度的影响。结果表明，熔池边界的温度梯度显著高于熔池内部，提高基板初始温度可有效降低温度梯度幅值，有望减小热应力和残余应力。 |
| 英文摘要: |
| Laser powder bed fusion (LPBF) additive manufacturing offers notable potentials for fabrication of complex structures in the aerospace and biomedical fields due to its capabilities of free-form fabrication and rapid manufacturing. However, LPBF involves extremely high heating and cooling rates as well as strong temperature gradients, inevitably leading to the generation of thermal stresses and residual stresses within the components. These stresses can severely compromise the mechanical properties of the components. Therefore, selecting appropriate parameters to reduce the magnitude and gradient of temperature during the LPBF process is of paramount importance for enhancing the quality of the printed parts. In this paper, a computational fluid dynamics model was used to assess the effects of substrate temperatures on the dynamic behavior and temperature field within melt pool. The model utilizes the volume-of-fluid technique to track powder shape changes, and incorporates recoil pressure and Marangoni effects. The results show that the temperature gradient is notably higher at melt pool border compared to melt pool interior, and increasing substrate temperature can effectively reduce temperature gradient. |
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