ABSTRACT
A paradigm shift is underway where pure classical materials, alloys, and conventional composites are being replaced by functionally graded materials (FGMs) for numerous applications in biomedical, aerospace, turbomachinery, and structural engineering. FGMs are beneficial for the components being operated in varying service conditions across their geometry, as different material properties are required at different locations on them. These materials are designed with spatial variation in properties (chemical, mechanical, magnetic, thermal, and electrical) by systematically coordinating with the functional requirement. The properties are tailored by varying one or more of the microstructure, porosity, and chemical composition at a time. The evolution of functionally graded additive manufacturing (FGAM) has transformed the modelling from geometric characteristics to performance basis by imparting performance-steered functionality to objects. Furthermore, integrating the opportunistic and restrictive aspects of additive manufacturing can enhance the design attributes like novelty and quality. The present study put forth a theoretical understanding of FGMs by summarizing the current modelling and optimization methods, fabrication, post-processing techniques, and characterization tools. In addition, the potential strategies to overcome various technological barriers and future research opportunities are demonstrated. Being a state-of-the-art and comprehensive review, it can be helpful for both academia and industry.
