激光粉末床熔融制备铝合金的研究进展

Research progress of aluminum alloys manufactured by laser powder bed fusion

  • 摘要: 铝合金因其低密度、高比强度以及优异的耐腐蚀性等综合性能,已成为航空航天、新能源汽车及高端装备制造等领域不可或缺的轻质结构材料. 激光粉末床熔融(Laser powder bed fusion, LPBF)作为激光增材制造的核心技术之一,为复杂结构铝合金构件的一体化成形提供了革命性的途径,是当前增材制造研究与应用的重要方向. 本文系统梳理了LPBF技术制备铝合金的研究进展,概述了LPBF技术的基本原理、相较于传统制造工艺的独特优势以及现阶段面临的主要挑战. 此外,全面综述了国内外在LPBF铝合金领域的研究概况,包括基础理论研究、工艺开发、材料创新及性能表征等方面的主要成果和动态,重点聚焦于Al–Cu (2xxx)、Al–Si (4xxx)、Al–Mg (5xxx)、Al–Zn–Mg–Cu (7xxx)等典型体系. 针对各体系在LPBF成形中的关键问题,尤其是Al–Cu与Al–Zn–Mg–Cu系的高热裂纹敏感性、Al–Si系的强塑性失衡以及Al–Mg系的强韧化需求,本文深入阐述了其热裂纹形成机理,并系统梳理了通过优化合金成分设计与工艺调控以抑制缺陷、优化组织的现有策略. 在此基础上,进一步分析了后热处理对调控析出相、改善综合性能的关键作用. 最后,系统分析了当前LPBF铝合金技术存在的核心问题,总结指出未来研究应转向“设计用于增材制造”的专用铝合金开发,通过成分–工艺–组织协同设计,实现低裂纹敏感性、高强韧性的综合目标,为推动LPBF铝合金的工程应用提供理论依据.

     

    Abstract: Owing to their exceptional combination of properties including low density, intrinsic light weight, high specific strength and hardness, and outstanding corrosion resistance, aluminum alloys have become core structural materials in critical sectors such as aerospace, automotive manufacturing, electronics, and telecommunications. The emergence of additive manufacturing (AM), particularly laser powder bed fusion (LPBF) technology, has revolutionarily transformed the design and manufacture of geometrically complex aluminum alloy components. These components are often difficult or impossible to produce using conventional manufacturing methods. As a core laser-based AM technology, LPBF uses a high-energy laser beam to selectively melt and fuse fine metallic powder layers within a precisely controlled atmosphere, enabling the layer-by-layer fabrication of intricate near-net-shape parts. This capability places LPBF at the forefront of cutting-edge AM research and industrial applications for high-value aluminum alloy parts. This review systematically synthesizes and analyzes the significant research progress achieved in the LPBF processing of aluminum alloys. It outlines the fundamental physical principles of the LPBF process and elucidates its unique advantages over traditional subtractive or formative manufacturing techniques (such as casting and forging), including unparalleled design freedom, minimal material waste, and the potential for rapid prototyping and customized production. This review candidly identifies the major challenges currently hindering the broader adoption of LPBF for aluminum alloys. These challenges include the persistently narrow LPBF processing window, difficulties in controlling metallurgical defects, the contradiction between simultaneous enhancement of strength and ductility (strength–ductility trade-off), pronounced sensitivity associated with columnar-grain-dominated solidification microstructures, significant hurdles in engineering application scale-up, and limitations in the existing alloy systems specifically optimized for the rapid solidification characteristics inherent to LPBF. Furthermore, this review provides a comprehensive overview of the current research status of several industrially crucial wrought aluminum alloy systems processed via LPBF. These primarily include Al–Cu (2xxx series), Al–Si (4xxx series), Al–Mg (5xxx series), and ultrahigh-strength Al–Zn–Mg–Cu (7xxx series) alloys. Focusing on the key challenges in LPBF processing across different alloy systems—particularly the high hot-cracking susceptibility of Al–Cu and Al–Zn–Mg–Cu alloys, the strength–ductility trade-off in Al–Si alloys, and the need for enhanced strength–toughness synergy in Al–Mg alloys—this review provides an in-depth discussion of hot-cracking formation mechanisms. It systematically outlines the current strategies for defect suppression and microstructure optimization through alloy composition design and process parameter regulation. Furthermore, the critical role of post-heat treatments in tailoring precipitate characteristics and improving the overall mechanical performance is examined. Finally, this review rigorously examines the core scientific and technological problems persisting within the current LPBF aluminum alloy technology. Building on this critical analysis, it proposes forward-looking perspectives for future research. The ultimate objective is to provide robust scientific insights and theoretical underpinnings to guide the development of next-generation LPBF-dedicated aluminum alloys. These alloys are expected to significantly reduce hot-cracking susceptibility while simultaneously achieving an optimized combination of high strength, high toughness, superior fatigue performance, and excellent corrosion resistance, thereby fully unlocking the potential of LPBF technology for demanding structural applications.

     

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