Effect of Powder Recycling on Mechanical Properties of Laser Powder Bed Stainless Steel for Nuclear Applications

增材制造被认为是核电站部件的一种替代制造工艺。这是由于该技术与传统制造路线相比具有许多优势，特别是在以较短的交货时间构建复杂的近净形状几何形状方面。此外，构建粉末可以多次回收，提供最小的浪费和显著的成本效益。罗尔斯·罗伊斯已经证明，与实际水平的粉末回收，机械性能保持在规范之内。然而，明确的回收限制并没有得到很好的理解。结果表明，合金的化学性质、粒度分布和粉末形貌会随着循环使用而发生变化。影响粉末状态的关键因素包括惰性气体纯度、构建几何形状、激光曝光时间和粉末管理策略。该项目的目的是支持劳斯莱斯在Raynesway工厂的持续努力，以了解粉末回收的影响以及它如何影响材料的机械性能。研究将在激光粉末床熔融（LPBF） 316不锈钢上进行，将包括粉末在不同阶段的暴露和回收后的彻底特征，广泛的冶金和微观结构研究，由机械测试性能，数据相关性和结果解释支持。

Additive manufacturing is proposed as an alternative manufacturing process for nuclear plant components. This is due to the numerous advantages the technology can offer over conventional manufacturing routes especially in constructing complex near net shape geometries with short lead times. In addition, build powder can be recycled numerous times, providing minimal wastage and a significant cost benefit. Rolls-Royce has demonstrated that with a practical level of powder recycling, mechanical properties remain within specification. A clear recycling limit is not, however, well understood. It has been shown that alloy chemistry, particle size distribution and powder morphology can vary with recycling. Key variables influencing powder condition include purity of inert gas, build geometry, laser exposure duration and powder management strategy.The objective of this project is to support the on-going efforts at the Rolls-Royce facility in Raynesway to understand the impact of powder recycling and how this influences mechanical behaviour of the material. Studies will be performed on laser powder bed fused (LPBF) stainless steel 316 and will include a thorough characterisation of the powder after different stages of exposure and recycling, an extensive metallurgical and microstructural investigation, supported by the performance of mechanical tests, data correlation and results interpretation.