MEHMET CAGIRICIMATERIALS SCIENCE AND ENGINEERING2021-12-032021-12-032021-08-13MEHMET CAGIRICI (2021-08-13). MEDIUM AND HIGH ENTROPY ALLOYS: DESIGN AND ADDITIVE MANUFACTURING. ScholarBank@NUS Repository.https://scholarbank.nus.edu.sg/handle/10635/209457Medium- and high-entropy alloys are considered as promising materials with an outstanding strength-ductility balance. Unique characteristics of these alloys lead to the distinctive combination of ductility, mechanical strength, and toughness and make them alternative to the existing structural materials used in engineering applications. However, an unexplored universe of the multi-principal element alloy concept, corresponding strengthening mechanisms that enhance mechanical properties, and the inadequate contribution of conventional manufacturing processes limit the development of new alloys. Recent developments in powder processing techniques, such as achieving high purity elemental and pre-alloyed powders, and employing additive manufacturing technologies, which can control an important part of microstructural evolution while fabricating metallic materials, allow us to design and develop promising medium- and high-entropy alloys. Thus, the design and production of novel alloys have been reconsidered and sought to address controlling microstructural development, promoting various strengthening mechanisms, and developing unique alloys without geometrical constraints in this thesis.enMedium Entropy Alloy, High Entropy Alloy, Alloy Development, Microstructural Evolution, Mechanical Properties, Additive ManufacturingThesis0000-0002-7129-5358