Functional gradient materials (FGMs), as a modern group of materials, can provide multiple functions and are able to well mimic the hierarchical and gradient structure of natural systems. Because biomedical implants usually substitute the bone tissues and bone is an organic, natural FGM material, it seems quite reasonable to use the FGM concept in these applications. These FGMs have numerous advantages, including the ability to tailor the desired mechanical and biological response by producing various gradations, such as composition, porosity, and size; mitigating some limitations, such as stress-shielding effects; improving osseointegration; and enhancing electrochemical behavior and wear resistance. Although these are beneficial aspects, there is still a notable lack of comprehensive guidelines and standards. This paper aims to comprehensively review the current scenery of FGM metallic materials in the biomedical field, specifically its dental and orthopedic applications. It also introduces various processing methods, especially additive manufacturing methods that have a substantial impact on FGM production, mentioning its prospects and how FGMs can change the direction of both industry and biomedicine. Any improvement in FGM knowledge and technology can lead to big steps toward its industrialization and most notably for much better implant designs with more biocompatibility and similarity to natural tissues that enhance the quality of life for human beings.

中文翻译：

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功能梯度金属生物材料：生物医学领域的技术、现状与未来展望

功能梯度材料（FGMs）作为一组现代材料，可以提供多种功能，并且能够很好地模拟自然系统的层次和梯度结构。由于生物医学植入物通常替代骨组织，而骨骼是一种有机、天然的 FGM 材料，因此在这些应用中使用 FGM 概念似乎很合理。这些 FGM 具有许多优点，包括能够通过产生各种等级（如成分、孔隙率和尺寸）来定制所需的机械和生物反应；减轻一些限制，例如应力屏蔽效应；改善骨整合；并增强电化学行为和耐磨性。尽管这些都是有益的方面，但仍然明显缺乏全面的指导方针和标准。本文旨在全面回顾 FGM 金属材料在生物医学领域的现状，特别是其牙科和骨科应用。它还介绍了各种加工方法，特别是对 FGM 生产有重大影响的增材制造方法，提到了它的前景以及 FGM 如何改变工业和生物医学的方向。FGM 知识和技术的任何改进都可以导致其工业化迈出一大步，最显着的是更好的植入物设计，具有更高的生物相容性和与自然组织的相似性，从而提高人类的生活质量。特别是对 FGM 生产有重大影响的增材制造方法，提到了它的前景以及 FGM 如何改变工业和生物医学的方向。FGM 知识和技术的任何改进都可以导致其工业化迈出一大步，最显着的是更好的植入物设计，具有更高的生物相容性和与自然组织的相似性，从而提高人类的生活质量。特别是对 FGM 生产有重大影响的增材制造方法，提到了它的前景以及 FGM 如何改变工业和生物医学的方向。FGM 知识和技术的任何改进都可以导致其工业化迈出一大步，最显着的是更好的植入物设计，具有更高的生物相容性和与自然组织的相似性，从而提高人类的生活质量。