The occurrence of structural defects during laser powder bed fusion (LPBF) impairs the mechanical properties of components fabricated by the technique. Therefore, having a good grasp of the mechanism of various structural defects is useful for guiding process maps. However, investigating melt-pool dynamics and corresponding defects using experiments is challenging. Numerical simulation thus represents a promising and visual way to reproduce these phenomena. In this study, predicated to first ensure accuracy, a two-dimensional (2D) model was numerically implemented by a phase field with a finite element method (FEM). Our model emphasises the interaction between neighbouring powders during heat duration with time-varying maximum intensity under different deposition parameters. Our simulation results indicate that the reinforcement of liquidity can significantly enhance the wettability of the neighbouring powder to release gas bubbles and extend the melt pool. Similarly, the remelting process also effectively eliminates porosity, which yields a smooth surface deposited in the previous layers to improve deposit densification. Our simulation also provided detailed insights into the evolution of liquid metal droplets away from “the elongated neck” and investigated the effect of scanning speed on the width of the melt pool of single tracks. Additionally, our model implemented a discrete FEM method with extremely refined free-triangle elements, which was accompanied by a decrease in computational cost and expressed good agreement with the experiments.

激光粉末床融合 (LPBF) 过程中结构缺陷的出现损害了该技术制造的部件的机械性能。因此，很好地掌握各种结构缺陷的机制对于指导流程图是很有用的。然而，使用实验研究熔池动力学和相应的缺陷是具有挑战性的。因此，数值模拟代表了一种重现这些现象的有前途的视觉方式。在这项研究中，首先确保精度，二维 (2D) 模型是通过有限元方法 (FEM) 的相场数值实现的。我们的模型强调在加热持续时间内相邻粉末之间的相互作用，在不同沉积参数下随时间变化的最大强度。我们的模拟结果表明，流动性的增强可以显着提高相邻粉末的润湿性，释放气泡并扩大熔池。类似地，重熔过程也有效地消除了孔隙率，这会产生沉积在先前层中的光滑表面，以提高沉积密度。我们的模拟还提供了对远离“细长颈部”的液态金属液滴演变的详细见解，并研究了扫描速度对单轨道熔池宽度的影响。此外，我们的模型实现了具有极其精细的自由三角形元素的离散 FEM 方法，伴随着计算成本的降低，并且与实验表现出良好的一致性。