DED熔池熔凝行为与枝晶形貌对拉伸强度的影响
Effect of Melting and Solidification Behavior and Dendrite Morphology of DED Melt Pool on Tensile Strength
宋博学 1王子生 1陈克强 1姜兴宇 1于天彪 2刘伟军 1杨国哲1
作者信息
- 1. 沈阳工业大学机械工程学院 沈阳 110870
- 2. 东北大学机械工程与自动化学院 沈阳 110819
- 折叠
摘要
熔池不稳定的瞬态对流与传热传质特征导致沉积层机械性能呈现强烈的各向异性.为探究沉积层枝晶形貌特征对拉伸性能强化差异的影响规律,构建面向热-流耦合的介观熔池动力学模型并探究熔池从产生到准稳态过程中的瞬态对流与热特征演变规律,获得了熔池凝固边界附近的温度梯度与凝固速率等凝固条件.通过WBM相场模型获得了沿凝固边界不同凝固条件诱发的枝晶形貌预测结果,同时探究了凝固条件的变化对一次枝晶臂间距、枝晶尖端半径和枝晶尖端过冷的影响规律,揭示了枝晶形貌特征对沉积层不同部位半定量拉伸强度的强化趋势,结果表明受枝晶形貌特征诱发的拉伸强化值在沉积层底部与中部的差异达到了 99MPa,进而对枝晶形貌特征对拉伸强度的强化机理进行了详细讨论.为实现单/多层定向能量沉积拉伸性能的可调可控提供了理论依据.
Abstract
The unstable transient convection and heat transfer characteristics of the melt pool lead to a strong anisotropy in the mechanical properties of the deposited layer.In order to investigate the influence of deposited layer dendrite morphology on the difference of tensile property strengthening,a mesoscopic melt pool dynamics model oriented to heat-flow coupling is constructed and the transient convection and thermal characteristics of the melt pool from generation to quasi-steady state are investigated,and the solidification conditions such as temperature gradient and solidification rate near the solidification boundary of the melt pool are obtained.The predicted results of dendrite morphology induced by different solidification conditions along the solidification boundary are obtained by WBM phase field model,and the effects of changes in solidification conditions on the primary dendrite arm spacing,dendrite tip radius and dendrite tip subcooling are also investigated.The strengthening trend of dendrite morphology on the tensile strength of different parts of the deposited layer is revealed,and the results show that the difference between the tensile strengthening value induced by dendrite morphology reache 99 MPa at the bottom and the middle of the deposited layer,and then the strengthening mechanism on the tensile strength of the deposite layer was discussed in detail.It provides a theoretical basis for achieving adjustable and controllable tensile properties of single/multi-layer directed energy deposition.
关键词
定向能量沉积/沉积层/熔池/相场/机械强度Key words
directed energy deposition/deposited layer/melt pool/phase field/mechanical properties引用本文复制引用
基金项目
辽宁省教育厅基本科研项目(LJKQZ20222299)
辽宁省揭榜挂帅项目(2022JH1/10800061)
辽宁省教育厅重点攻关项目(LJKZZ20220023)
沈阳市科技计划(23-503-6-01)
出版年
2024
NETL
NSTL
万方数据