激光选区熔化成形蜂窝嵌套晶格结构的压缩变形性能及微观组织研究

Compressive properties and deformation behavior of bionic honeycomb nested lattice structures formed by laser selective melting

摘要:

蜂窝结构因其轻质、高强度和能量吸收等特性而被广泛应用于材料轻量化设计领域。然而，传统蜂窝结构侧面性能差，结构稳定性不好。为了解决这些问题，本文将三种杆单元晶格结构嵌套在蜂窝空腔内，从而得到新的蜂窝嵌套晶格结构。以AlSi10Mg粉末为材料，采用激光选区熔化（SLM）技术制备蜂窝嵌套新型BCC晶格结构（HC-N-BCC）、蜂窝嵌套对称杆晶格结构（HC-SP）、蜂窝嵌套新型萤石晶格结构（HC-N-F）和空蜂窝结构（HC-E）不同相对密度的试样，并进行侧面压缩力学性能测试、宏微观变形机制和能量吸收分析。结果表明：蜂窝嵌套晶格结构侧面压缩性能大幅优于空蜂窝结构，在46%相对密度下，HC-SP结构的压缩模量和峰值应力比HC-E高43%和44.7%，在50%应变下，其能量吸收值（）和破碎力效率（CFE）分别是HC-E的7.7倍和5.3倍。当桁架晶格嵌入蜂窝空腔后，使得蜂窝外壳从瞬间破碎变形变成缓慢均匀变形，这极大改善了蜂窝结构的压缩稳定性。桁架体积占整体结构的占比越大，蜂窝嵌套晶格结构的性能提升效果越好。

Abstract:

Honeycomb structures are widely used in lightweight material design due to their characteristics of being lightweight, high strength, and energy-absorbing. However, conventional honeycomb structures have poor lateral performance and structural stability. To address these issues, this study nests three types of truss rod unit lattice structures within the honeycomb cavities to obtain a new honeycomb nested lattice structure. Using AlSi10Mg powder as the material, the selective laser melting (SLM) technique was employed to fabricate samples with different relative densities, including the new BCC honeycomb nested lattice structure (HC-N-BCC), honeycomb nested symmetric rod lattice structure (HC-SP), new fluorite-type honeycomb nested lattice structure (HC-N-F), and hollow honeycomb structure (HC-E). These samples were then tested for lateral compression mechanical properties, macro- and micro-scale deformation mechanisms, and energy absorption. The results show that the lateral compression performance of the honeycomb nested lattice structures is significantly superior to that of the hollow honeycomb structure. At 46% relative density, the HC-SP structure exhibits a compression modulus and peak stress that are 43% and 44.7% higher than those of HC-E, respectively, and at 50% strain, its energy absorption (EA) and crushing force efficiency (CFE) are 7.7 and 5.3 times higher than those of HC-E. When truss unit lattices are embedded in the honeycomb cavities, the honeycomb shell deforms gradually and uniformly instead of fracturing instantly, greatly improving the compressive stability of the honeycomb structure. Furthermore, the larger the proportion of the truss volume in the overall structure, the greater the performance improvement of the honeycomb nested lattice structure.