Design of metal structures of custom composition using additive manufacturing

添加剂制造(AM)提供了一种新的制造模式，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可定制(分级)化学成分的有前途的金属结构的发展，如果设计正确，这种结构可以用来取代现在通过连接不同合金制成的模块化元件而形成的部件。定制的组合结构可以在各种行业中得到应用，特别是能源、汽车和航空航天，在这些行业中，通常需要管理极端的热和机械条件。使用AM控制结构内的成分将允许设计者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)。虽然化学成分分级为创造新的杰出材料提供了独特的机会，但仍需要了解不同的金属如何在AM过程中紧密结合，以系统地实现所需的性能。本博士学位旨在通过建立用于激光AM的合适材料组合的识别指南来填补这一知识空白，同时制造没有结构缺陷(例如，裂纹和空洞)的可靠部件。这将通过确定作为打印激光参数的函数的打印组件的界面区域(不同材料接触的位置)的结构和热行为来实现。该项目建立在添加剂制造中心(CFAM)开发的关于将计算材料科学技术应用于激光AM以识别和选择合适的材料组合的专业知识的基础上。将使用最先进的AM软件来设计具有所确定材料的部件，以满足最终部件所需的性能。正确设计这些复杂部件的关键是对印刷结构中形成的界面进行表征和测试。博士生将结合AM和计量学技术、先进的材料测试、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。被任命的学生将作为CfAM一个充满活力的跨学科团队的一员，CfAM是全球最大的添加剂制造和3D打印研究中心之一。

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.