Design of metal structures of custom composition using additive manufacturing

增材制造（AM）提供了一种新的制造范式，几乎可以完全控制材料的加工和连接方式。这种多功能性导致了有前途的可定制（分级）化学成分的金属结构的发展，如果设计正确，可以用来取代现在通过连接由不同合金制成的模块化元素而形成的组件。定制组合结构可以在各种行业中找到应用，特别是能源，汽车和航空航天，这些行业通常需要管理极端的热和机械条件。使用增材制造来控制结构内的成分将允许设计师在特定位置调整机械和物理性能（例如密度、热膨胀系数、铁磁性、强度等），从而提高零件性能。虽然分级化学成分为创造新的优秀材料提供了独特的机会，但需要了解在增材制造过程中不同的金属如何紧密结合以系统地实现所需的性能。该博士旨在通过建立用于激光增材制造的合适材料组合的识别指南来填补这一知识空白，同时制造无结构缺陷（例如裂纹和空洞）的可靠部件。这将通过确定打印组件的界面区域（不同材料接触的位置）的结构和热行为作为打印激光参数的函数来完成。该项目建立在增材制造中心（CfAM）开发的专业知识的基础上，该中心将计算材料科学技术应用于激光增材制造，以识别和选择合适的材料组合。最先进的增材制造软件将用于用确定的材料设计零件，以满足最终零件的期望性能。对打印结构中形成的界面进行表征和测试将有助于这些复杂部件的正确设计。博士生将结合增材制造和计量技术、先进材料测试、显微镜和数值建模来开发这些结构，从而获得与先进制造和材料研究相关的广泛技能和知识。被任命的学生将成为CfAM（全球最大的增材制造和3D打印研究中心之一）充满活力的跨学科团队的一员。

Additive Manufacturing (AM) offers a new fabrication paradigm that allows almost total control over how materials are processed and connected. This versatility has led to the development of promising metal structures of customisable (graded) chemical composition which, if correctly designed, could be used to replace components now formed by joining modular elements made of different alloys. Structures of customised composition could find applications in a variety of industries especially energy, automotive and aerospace where it is oftenrequired management of extreme thermal and mechanical conditions. Using AM to control the composition within a structure would allow designers to tunemechanical and physical properties in specific locations (e.g. density, coefficients of thermal expansion, ferromagnetism, strength, etc.) and therefore enhance partperformance.Although grading chemical composition offers unique opportunities to create newoutstanding materials, there is a requirement to understand how different metalscan be intimately combined during AM to systematically achieve desired properties.This PhD aims to fill this knowledge gap by establishing guidelines for the identification of suitable material combinations for use in laser-based AM whilst fabricating reliable parts with no structural defects (e.g. cracks and voids). This will be accomplished by determining the structural and thermal behaviour of theinterface regions of the printed component (locations where dissimilar materials are in contact) as a function of the printing laser parameters. The project builds on the expertise developed at the Centre for Additive Manufacturing (CfAM) on the application of computational materials science techniques to laser AM to identify and select suitable material combinations. State-of-the-art AM software will be used to design parts with the identified materials in such a way as to satisfy the desired properties of the final part. Instrumental to the correct design of these complex parts will be the characterisation and testing of the interfaces formed in the printed structures. The PhD student will develop these structures with a combination of AM and metrology techniques, advanced materials testing, microscopy and numerical modelling, thereby gaining a broad set of skills and knowledge relevant to advanced manufacturing and materials research. The student appointed will work as part of a dynamic interdisciplinary team at CfAM, one of the largest research centres for additive manufacturing and 3D printing worldwide.