Friction stir processing (FSP) is a rapidly emerging newer solid-state technique for composite fabrication. It involves surface modification which in turn enables successful adaptation of surface properties through plastic deformations in solid state. During initial years of FSP inception, it was primarily employed in development of metal matrix composites of light metal alloys like aluminum. However, recently, it has gained an alluring role in fabrication of composites of various nonferrous and ferrous metal alloys as well as of polymers. In addition to composite fabrication, FSP has evolved as a revolutionary technique in developing functionally graded systems/surfaces (FGS) of metal matrix. This article covers all aspects of FSP in which reinforcement particles are embedded in the base matrix to develop composites and FGS. It presents a critical review on domains of recent developments, effects of different types of reinforcement particles and properties enhancement of composites, and FGS fabrication. In addition to this, various issues, challenges, and future work that demand attention are systematically addressed.

中文翻译：

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通过摩擦搅拌工艺在固态复合材料和功能梯度体系的固态制备中的最新进展综述

搅拌摩擦加工（FSP）是一种快速兴起的，用于复合材料制造的新型固态技术。它涉及表面改性，这反过来又可以通过固态塑性变形成功地适应表面特性。在FSP成立的最初几年中，它主要用于开发轻金属合金（如铝）的金属基复合材料。然而，最近，它在各种有色金属和黑色金属合金以及聚合物的复合材料的制造中起了诱人的作用。除了复合制造之外，FSP在开发金属基体的功能梯度系统/表面（FGS）方面已发展成为一项革命性技术。本文涵盖了FSP的所有方面，其中将增强颗粒嵌入基础基质中以开发复合材料和FGS。它对近期的发展领域，不同类型的增强颗粒的影响以及复合材料的性能增强以及FGS的制造提出了重要的评论。除此之外，还系统地解决了需要注意的各种问题，挑战和未来工作。