Alloy Design for Metal Additive Manufacturing

Abstract

Fusion-based additive manufacturing (AM) is constantly evolving and contains a significant body of interesting research and development. Many aspects of the technology have yet to be addressed, and the understanding of AM processes is continuously improved to develop new theories and solutions to tackle issues in AM. In essence, there are two approaches to minimize the defect formation in fusion-based AM: The first one is to optimize the process parameters and surrounding environment to minimize the defects; the second approach is to tailor the material's inherent properties to fit a specific AM process to reduce the risk of forming the defects and undesirable metallurgical features. The ideal solution would be a holistic combination of the two approaches; however, this is yet to be accomplished. This chapter will focus on the material's aspects of defect formation mechanisms with aims (i) to assist the assessment of the suitability of existing alloys and (ii) to design new alloys for a given AM process. In this chapter, Section Motion Encoding and MRE Sequences gives an overview of the materials currently used in fusion-based AM, highlighting the common defects. Then, Section Motion Encoding and MRE Sequences focuses on the material's properties that affect the defect formation in relation to the AM process characteristics. Section Motion Encoding and MRE Sequences explores the current state-of-the-art understanding of the main metallurgical mechanisms responsible for forming the defects, laying a basis for developing an alloy design methodology for minimizing the risks of defect formation and obtaining desirable microstructure. Finally, several examples of alloy design will be given, demonstrating the use of the methodology. The authors hope that this chapter can provide the necessary knowledge and a foundation that help the readers in the evaluation of the suitability, the design, and search for alloy composition for AM.