基于修正Gibson-Ashby模型的钛合金多孔材料各向异性调控

Anisotropy Control of Titanium Alloy Porous Materials Based on Modified Gibson-Ashby Model

摘要:

根据不同方向的承载需求，开展多孔材料力学性能的各向异性调控，可以有效提高材料承载效率，更好地满足轻量化需求。本研究以G7、bccz型TC4钛合金多孔材料为例，提出了考虑孔结构几何参数的杆系多孔材料修正Gibson-Ashby模型，可为多孔材料的各向异性精细化调控提供指导；基于该计算模型，通过对传统胞元几何参数调整，获得一系列具有相似构型、不同性能的各向异性多孔材料，并通过正向及侧向压缩试验，研究了胞元几何参数对多孔材料各向抗压强度及破坏模式的影响，验证了修正模型的有效性。研究表明，杆系多孔材料的抗压强度由其胞元内部微杆件的长径比及倾斜角度决定，通过调整杆件倾斜角度可有效进行多孔材料各向力学性能的调控。相同密度下，将斜杆倾斜角度从35°提高至55°，可使G7、bccz型钛合金多孔材料的正向抗压强度大幅提升105%和45%，而侧向抗压强度仅损失16%和13%。

Abstract:

According to the varying load in different directions, the anisotropy control of porous materials can significantly enhance the load-bearing efficiency of materials, thus better addressing the need for lightweight designs. In this research, a modified Gibson-Ashby model for strut-based porous materials accounting for geometric parameters was established by taking G7 and bccz types of TC4 porous materials as examples. This model can serve as a guide for the precise control of anisotropy for strut-based porous materials. Based on this model, a series of anisotropic porous materials with similar configurations but distinct properties were created by adjusting geometric parameters of common unit cells. The effects of unit cell geometric parameters on the anisotropic compressive strength and failure modes of porous materials were investigated through vertical and lateral compressive tests, thereby validating the efficacy of the modified model. The results show that the compressive strength of strut-based porous materials is primarily determined by the aspect ratio and the inclination angle of their struts. By fine-tuning the inclination angle of struts, the anisotropic mechanical properties of porous materials can be effectively modulated. Under the same density, increasing the inclination angle of the diagonal struts from 35° to 55° can significantly increase the vertical compressive strength of G7 and bccz types of TC4 porous materials by 105% and 45%, respectively, with only a minor reduction in lateral compressive strength of 16% and 13%, respectively.