Processing, Microstructure and Hydrogen embrittlement of 3D printed Inconel718

增材制造（AM），也被称为3D打印，有望彻底改变材料的设计、供应和制造方式，在汽车、能源、医疗和航空航天应用方面具有巨大潜力。在所有增材制造中，粉末床熔合是制造高精度复杂金属部件的最有效方法。Inconel718是应用最广泛的镍基合金之一，具有良好的可焊性、优异的抗疲劳、耐热腐蚀、耐磨损和高强度，是天然气和石油等高温应用的理想选择。尽管对Inconel 718的微观结构和力学行为进行了广泛的研究，但对于增材制造工艺参数、微观结构和性能之间的关系，特别是氢脆，仍然缺乏了解。因此，本项目将使用激光粉末床熔合来制造不同打印参数的Inconel718。随后，将进行详细的研究，以检查合金从单道沉积到多道沉积以及随后的热处理中的显微组织演变。机械测试将在打印和热处理条件下进行，有和没有带电氢，以研究合金对氢脆的敏感性。-制造：将打印参数（即激光强度，曝光时间，激光光斑距离，舱口间距，层厚度和扫描策略）与固化和凝固微观结构相关。-在室温和高温下对打印合金进行充氢和不充氢的单轴拉伸试验，研究氢脆。-微观结构表征：通过光学、扫描/透射电子显微镜（包括EDX）和x射线衍射来表征打印和变形样品的微观结构形态、晶体相、晶体学取向和化学分布。

Additive manufacturing (AM), also known as 3D printing, is expected to revolutionise the way of designing, supplying and making materials, holding great potential for automotive, energy, medical and aerospace applications. Amongst all AM, powder bed fusion is the most effective method to fabricate complex metallic components with high accuracy.Inconel718 is one of the most widely used nickel-based alloys thanks to its good weldability, excellent resistance to fatigue, to hot corrosion and to wear and high strength, making it an excellent candidate for high-temperature applications including in gas and oil.Although the microstructure and mechanical behaviour of Inconel 718 have been extensively studied, there is still significant lack of understanding regarding the relationship between AM process parameters, microstructure and performance - in particular the hydrogen embrittlement. Therefore, this project will use the laser powder bed fusion to fabricate Inconel718 with various print parameters. Subsequently, detailed studies will be carried to examine the microstructure evolution of the alloy from single to multiple tracks of deposition and in subsequent heat treatments. Mechanical tests will be done on both as-printed and heat-treated conditions with and without charged Hydrogen to study the susceptibility of the alloy to hydrogen embrittlement.Tasks will be carried out in this project:- Fabrication: Relating print parameters (i.e laser intensity, exposure time, laser spot distance, hatch spacing, layer thickness and scanning strategy) to consolidation and solidification microstructure.- Uniaxial tension testing at room and elevated temperatures will be carried out on the printed alloy with and without the charging of Hydrogen to study the hydrogen embrittlement. - Microstructure characterisation: Microstructure morphology, crystal phases, crystallographic orientations and chemical distribution of as-printed and deformed samples will be characterised by optical and scanning/transmission electron microscopy (including EDX) and X-ray diffraction.