High performance realization of functionally graded materials based on integrated optimal design and additive manufacturing: A review

Functionally graded materials (FGMs) are special advanced composite materials. The significant capabilities of additive manufacturing (AM) technology in material and structural control offer promising opportunities for designing and fabricating next-generation FGMs. However, the current fabrication of FGMs using AM technology (AM-FGMs) is often relies on empirical methodologies, limiting the exploitation of the distinctive features of high-performance FGMs. Therefore, we propose a "bottom-to-top" design concept for AM-FGMs aimed at achieving high performance, versatility, and suitability for industrial applications in extreme environments, integrating optimal design with AM technology. Initially, this paper discusses the optimal design of AM-FGMs, emphasizing multi-scale and multi-functional design driven by AM technology. Subsequently, the advantages and disadvantages of different AM-FGMs fabrication methods, process optimization, and post-processing optimization are discussed. Finally, the versatile applications, research challenges, and prospects of AM-FGMs are summarized. This work contributes to advancing the realization of high-performance AM-FGMs and offers valuable guidance for the fabrication in the future.