For successful fabrication of components using additive manufacturing techniques such as powder bed fusion (PBF), directed energy deposition, and laser cladding of an alloy on to a substrate of a dissimilar one, an interpenetrating interface morphology is essential for a good interface strength. The physical mechanisms behind the formation of different solidified interface morphologies after single track laser PBF of Inconel 718 powders on to the 316L austenitic stainless stress substrate were investigated by recourse to numerical simulations, which combine micron-scale fluid dynamics and solidification protocols with nanosecond-level thermal diffusion processes. These were complemented with parametric experiments to verify the simulations. Results show that an interface with the “fish scale” morphology can occur under certain combinations of process parameters, and because of the combined actions of recoil pressure, Marangoni forces, surface tension and melt pool shape. Three distinct morphologies that depend on the melt pool width and depth are identified and the interfacial areas for each of them are computed. The influence of the processing conditions that not only dictate the geometric parameters of the melt pool but also the degree of alloying and the resulting grain morphology within the interface microstructure were elucidated.

为了使用增材制造技术成功制造组件，例如粉末床熔融 (PBF)、定向能量沉积和将合金激光熔覆到不同基材上，互穿界面形态对于良好的界面强度至关重要。Inconel 718 粉末在 316L 奥氏体不锈钢应力基体上进行单道激光 PBF 后形成不同凝固界面形态背后的物理机制通过数值模拟进行研究，该数值模拟将微米级流体动力学和凝固协议与纳秒级相结合热扩散过程。这些与参数实验相辅相成，以验证模拟。结果表明，由于反冲压力、马兰戈尼力、表面张力和熔池形状的共同作用，在某些工艺参数组合下会出现具有“鱼鳞”形态的界面。确定了取决于熔池宽度和深度的三种不同形态，并计算了每种形态的界面面积。阐明了加工条件的影响，这些条件不仅决定了熔池的几何参数，而且还决定了合金化程度和界面微观结构内产生的晶粒形态。确定了取决于熔池宽度和深度的三种不同形态，并计算了每种形态的界面面积。阐明了加工条件的影响，这些条件不仅决定了熔池的几何参数，而且还决定了合金化程度和界面微观结构内产生的晶粒形态。确定了取决于熔池宽度和深度的三种不同形态，并计算了每种形态的界面面积。阐明了加工条件的影响，这些条件不仅决定了熔池的几何参数，而且还决定了合金化程度和界面微观结构内产生的晶粒形态。