中国空间科学技术

中国空间科学技术 ›› 2024, Vol. 44 ›› Issue (2): 16-29.doi: 10.16708/j.cnki.1000-758X.2024.0018

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选区激光熔化三维点阵结构尺寸效应研究进展

彭成宽，祁俊峰，邵珩   

  1. 北京卫星制造厂有限公司，北京100190
  • 出版日期:2024-04-25 发布日期:2024-04-09

Research progress on size effect of three-dimensional lattice structure manufactured by selective laser melting

PENG Chengkuan，QI Junfeng，SHAO Heng   

  1. Beijing Satellite Manufacturing Co.，Ltd.，Beijing 100190，China
  • Published:2024-04-25 Online:2024-04-09

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摘要： 三维点阵结构技术是兼具轻量化和功能-结构一体化设计的创新型技术，结构成形所依赖的选区激光熔化技术在成形跨尺度结构和渐变结构时面临严重的尺寸效应问题，制约了三维点阵结构的应用及推广。特征结构的“形”、“性”特征是评价打印质量的重要标准，因此，以三维点阵的特征结构——杆和薄壁作为研究对象，系统梳理了尺寸效应的相关研究。首先，从温度场出发，阐述了特征尺寸对宏观热累计及介观熔池尺寸、温度梯度、冷却速率的影响规律，为进一步“形”、“性”分析提供依据；其次，缺陷和微观组织形貌是控“形”的主要内容，因此总结了特征尺寸对微观孔隙率、尺寸精度、粗糙度三种缺陷程度及晶粒尺寸、排向两种微观组织特征的影响规律，并对其产生的机理进行了分析；最后，对比了不同缺陷和微观组织特征对力学性能的影响，为特征结构控“性”提供借鉴。合理的工艺参数选择与特征尺寸相互配合，可以有效改善打印质量，提高特征结构的力学性能，为跨尺度结构及渐变结构的工艺方案设计提供参考，同时也为极致轻量化的探索提供了思路。

关键词: 尺寸效应, 选区激光熔化, 三维点阵结构, 特征尺寸, 多孔结构

Abstract: The three-dimensional lattice structure technology is an innovative technology with both lightweight and function-structure integrated design.The selective laser melting technology for lattice structure forming faces serious size effect problems when forming cross-scale structures and gradient structures，which restricts the application and promotion of lattice structure.The “shape” and “performance” of the characteristic structure are important criteria for evaluating the printing quality.Therefore，taking the characteristic structure of three-dimensional lattice-struts and thin walls as the research objects，the relevant researches on size effect are systematically reviewed.Firstly，basing on the analysis of temperature field，this paper expounds the influence law of characteristic size on macroscopic heat accumulation and mesoscopic melt pool size，temperature gradient and cooling rate，which provides a basis for further “shape” and “performance” analysis.Secondly，defects and microstructure morphology are the main content of controlling “shape”.Therefore，the influences of characteristic size on three kinds of defects degree (microporosity，dimensional accuracy and roughness)，as well as two kinds of microstructural characteristics (grain size and orientation) are summarized，and the forming mechanism is analyzed.Finally，the influences of different defects and microstructure characteristics on the mechanical properties are compared to provide reference for the control of “performance” for the lattice structure.The research work of some scholars also shows that reasonable process parameter selection for specific feature size can effectively improve the printing quality and mechanical properties of the feature structure，which provides a reference for the process design of cross-scale structures and gradient structures，and also sparks inspiration for the exploration of extreme lightweight.

Key words: size effect, selective laser melting, lattice structure, characteristic size, porous structure