Chandra Shubham, Wang Chengcheng, Tor Shu Beng, Ramamurty Upadrasta, Tan Xipeng
Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
Nat Commun. 2024 Apr 11;15(1):3094. doi: 10.1038/s41467-024-47257-w.
Microstructure control in metal additive manufacturing is highly desirable for superior and bespoke mechanical performance. Engineering the columnar-to-equiaxed transition during rapid solidification in the additive manufacturing process is crucial for its technological advancement. Here, we report a powder-size driven melt pool engineering approach, demonstrating facile and large-scale control in the grain morphology by triggering a counterintuitive response of powder size to the additively manufactured 316 L stainless steel microstructure. We obtain coarse-grained (>100 μm) or near-monocrystalline microstructure using fine powders and near-equiaxed, fine-grained (<10 μm) microstructure using coarse powders. This approach shows resourceful adaptability to directed energy deposition and powder-bed fusion with no added cost, where the particle-size dependent powder-flow preheating effects and powder-bed thermophysical properties drive the microstructural variations. This work presents a pathway for leveraging feedstock particle size distribution towards more controllable, cost-effective, and sustainable metal additive manufacturing.
金属增材制造中的微观结构控制对于获得卓越且定制化的机械性能极为重要。在增材制造过程的快速凝固过程中设计柱状晶向等轴晶的转变对其技术进步至关重要。在此，我们报告一种粉末尺寸驱动的熔池工程方法，通过引发粉末尺寸对增材制造的316L不锈钢微观结构的反直觉响应，展示了对晶粒形态的简便且大规模控制。我们使用细粉获得粗晶粒（>100μm）或近单晶微观结构，使用粗粉获得近等轴细晶粒（<10μm）微观结构。这种方法对定向能量沉积和粉末床熔合显示出丰富的适应性且无需额外成本，其中依赖于颗粒尺寸的粉末流预热效应和粉末床热物理性质驱动微观结构变化。这项工作为利用原料粒度分布实现更可控、更具成本效益和可持续的金属增材制造提供了一条途径。
