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

增材制造被提议作为核电站部件的替代制造工艺。这是由于该技术可以提供超过传统制造路线的许多优点，特别是在以较短的交货时间构造复杂的近净形几何形状方面。此外，构建粉末可以多次回收，提供最小的浪费和显着的成本效益。罗尔斯·罗伊斯公司已经证明，在实际的粉末回收水平下，机械性能保持在规格范围内。然而，一个明确的回收限制并没有得到很好的理解。它已被证明，合金化学，粒度分布和粉末形态可以随着回收而变化。影响粉末状态的关键变量包括惰性气体的纯度、构建几何形状、激光照射时间和粉末管理策略。该项目的目标是支持罗尔斯·罗伊斯公司位于Raynesway的工厂正在进行的努力，以了解粉末回收的影响以及这如何影响材料的机械性能。研究将在激光粉末床熔融（LPBF）不锈钢316上进行，并将包括在暴露和回收的不同阶段后对粉末进行彻底表征，广泛的冶金和微观结构调查，并得到机械测试，数据相关性和结果解释的支持。

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.