Influence of molten-pool cooling rate on solidification structure and mechanical property of laser additive manufactured Inconel 718
Influence of molten-pool cooling rate on solidification structure and mechanical property of laser additive manufactured Inconel 718
复制标题
熔池冷却速率对激光增材制造Inconel 718凝固组织和力学性能的影响
DOI：
10.1016/j.jmrt.2022.06.162
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Lijun Song
中科院分区：
文献类型：
--
作者：
Hui Xiao;Xuanyu Liu;Wenjia Xiao;Jingwei Yang;Cong Li;Yanqin Li;Lijun Song
凝固结构和冷却速率之间的关系对于优化工艺参数以实现增材制造部件的期望机械性能是至关重要的。然而，在激光增材制造（LAM）期间建立上述关系仍然具有挑战性。在本工作中，熔池温度的实验测量使用双色高温计在LAM的Inconel 718。研究了激光加工工艺参数、熔池冷却参数与凝固组织和力学性能之间的关系。结果表明，随着冷却速率从480 °C/s增加到2630 °C/s，Nb偏析比从9.30减小到4.26，Laves相颗粒的体积分数从14.5%减小到4.8%。一次枝晶臂间距λ 1与冷却速率ε之间的定量关系确定为λ 1 =438.5 ε-0.577 3。推荐采用高冷却速度和合理的熔池寿命的激光工艺参数，以达到抗拉强度和塑性的良好结合，减少Nb偏析、Laves体积分数和冶金缺陷。该研究建立了凝固组织与冷却速度之间的定量关系，为在线评价凝固组织和力学性能提供了可能的方法。
The relationship between solidification structure and cooling rate is critical for optimizing processing parameters to achieve desired mechanical property of additive manufactured parts. However, the establishment of the above relationship during laser additive manufacturing (LAM) is still challenging. In the present work, the molten-pool temperature was experimentally measured using a two-color pyrometer during LAM of Inconel 718. The relationship among laser processing parameters, molten-pool cooling parameters, solidification structure and mechanical property was investigated. The results showed that the Nb segregation ratio decreases from 9.30 to 4.26 and the volume fraction of Laves-phase particles decreases from 14.5% to 4.8% as the cooling rate increases from 480 °C/s to 2630 °C/s. The quantitative relationship between primary dendritic arm spacing λ 1 and cooling rate ε was determined as λ 1 =438.5∗ε −0.577 3 . The laser processing parameter that creats the high cooling rate and rational molten-pool lifetime is recommend to achieve a good combination of tensile strength and plasticity, as it reduces the Nb segregation, the Laves volume fraction and the metallurgical defect. This work establishes the quantitative relationship between solidification structure and cooling rate, and provides the potential method for online evaluation of solidification structure and mechanical property.