Directed energy deposition (DED) is an additive manufacturing (AM) process where a laser is used to fuse a metal powder onto a substrate. The powder is deposited in a layer-by-layer fashion, and each deposited track is referred to as the clad. Large thermal gradients that occur during DED can cause changes in the clad geometry as well as deformation of the substrate and final part. Thermal behavior of DED manufactured parts and mitigation of thermal distortion has been addressed in the literature, but these studies mainly focused on material properties while neglecting the effect of thermal distortion on part geometry. One of the mitigation strategies that has been widely tested and accepted is substrate preheating. This study uses analytical and experimental models to observe changes in clad geometry when energy input to the part is varied by adjusting process parameters and preheating the substrate. A method to quantify substrate energy, or the amount of heat energy the substrate holds, is found as well as a relationship between the substrate energy and clad geometry. The geometry of the clad can be controlled by controlling the total energy added to the clad.

定向能量沉积（DED）是一种增材制造（AM）工艺，其中使用激光将金属粉末熔合到基板上。粉末以逐层方式沉积，每个沉积的轨迹都称为包层。在DED期间发生的大的热梯度会导致包层几何形状的变化，以及基板和最终零件的变形。文献中已经解决了DED制造零件的热行为和减轻热变形的问题，但是这些研究主要集中在材料性能上，而忽略了热变形对零件几何形状的影响。基材预热已被广泛测试和接受，是一种缓解策略。这项研究使用分析和实验模型来观察通过调整工艺参数和预热基板来改变输入到零件的能量时覆层几何形状的变化。找到量化衬底能量或衬底所保持的热能的量的方法，以及衬底能量与包层几何形状之间的关系。可以通过控制添加到包层的总能量来控制包层的几何形状。