Abstract Direct Energy Deposition (DED) is being widely used to repair damaged components to increase service life and economical operation. Process parameters including laser power, traverse speed and the mass flowrate of the feedstock material may be adapted in-situ. This allows bespoke repair strategies to be devised to match the variability in the condition of the parts supplied that require repair; however, there are limited modelling techniques that allow the adaptive control within the DED process to be represented. In this study, a novel modelling strategy is presented which allows the DED process to be modelled in a transient state. This allows varying process parameters to be included in the model, to predict the transient track geometry and the associated thermomechanical effects of the process. Here, a single-track deposition of IN718 with a varying cross section has been modelled utilising the proposed approach. The modelling methodology was validated with a corresponding experimental study on a deposition made using a Nd:YAG laser source with a coaxial nozzle. An in-situ modification was generated by variation of the laser power. The track profile was compared against focus variation microscopy images and the thermomechanical portion of the model was validated through in-situ temperature measurements, micrographs and residual stress, obtained from neutron diffraction measurements. A good agreement between the predicted and experimental findings were observed. The track height and width were predicted with a maximum error of 6.5% and 7.6% respectively. The peak temperature and residual stress were predicted within 6.2% and 11.4% respectively. Overall, the modelling method presented will allow complex and bespoke multi parameter repair strategies to be rapidly developed.

中文翻译：

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一种通过直接能量沉积过程参数原位修改来预测瞬态轨道几何形状和热机械效应的新型数值方法

摘要 直接能量沉积（DED）被广泛用于修复损坏的部件，以提高使用寿命和经济运行。包括激光功率、横动速度和原料材料的质量流量在内的工艺参数可以原位调整。这允许设计定制的维修策略以匹配需要维修的供应部件的条件的可变性；然而，允许表示 DED 过程中的自适应控制的建模技术有限。在这项研究中，提出了一种新颖的建模策略，该策略允许在瞬态下对 DED 过程进行建模。这允许将变化的过程参数包含在模型中，以预测过程的瞬态轨道几何形状和相关的热机械效应。这里，使用所提出的方法对具有不同横截面的 IN718 的单轨沉积进行了建模。该建模方法通过对使用带有同轴喷嘴的 Nd:YAG 激光源进行的沉积进行的相应实验研究来验证。通过改变激光功率产生原位修改。将轨迹轮廓与焦点变化显微镜图像进行比较，并通过原位温度测量、显微照片和从中子衍射测量获得的残余应力验证模型的热机械部分。观察到预测结果和实验结果之间的良好一致性。预测轨道高度和宽度的最大误差分别为 6.5% 和 7.6%。预计峰值温度和残余应力分别在 6.2% 和 11.4% 以内。