Synchronous involvement of topology and microstructure to design additively manufactured lattice structures
Synchronous involvement of topology and microstructure to design additively manufactured lattice structures
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DOI：
10.1016/j.addma.2022.102618
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发表时间：
2022-02-16
影响因子：
11
通讯作者：
Hazeli, Kavan
中科院分区：
文献类型：
--
作者：
Babamiri, Behzad Bahrami;Mayeur, Jason R.;Hazeli, Kavan
本文提出了一种系统的方法来优化微观结构（例如，晶体织构）和拓扑结构（例如，单元格和支柱），同时提高增材制造金属晶格结构（AMLS）的机械性能，即屈服强度和塑性流变应力。采用快速傅立叶变换（EVP-FFT）晶体塑性（CP）模拟确定了最佳微观结构。校正了CP模型参数，测量了固溶时效（STA）增材制造（AM） Inconel 718多晶样品的宏观应力应变响应和显微组织数据。由于单晶晶粒相对于加载方向的晶体取向对材料的力学行为有重大影响，因此使用应力投影因子分析来确定四种候选纹理，以探索给定的单元胞拓扑结构。全场晶体塑性模拟用于确定每个考虑的织构的宏观屈服面参数，从而实现宏观晶格单元模拟，以解释潜在的微观结构。利用标定的微结构相关屈服面，研究了不同微结构对相同相对密度下不同LS拓扑力学响应的影响。结果表明：在平行于加载方向的< 111 >晶型织构中，其抗拉屈服强度和抗压屈服强度分别比AM STA IN718织构提高20%和58%；此外，当这种织构与罗菱形拓扑结构结合使用时，结果表明，与之前没有直接考虑微观结构的优化AMLS设计相比，屈服强度和弹性模量都提高了50%。在优化过程中同时考虑了微观结构和拓扑结构，从而显著提高了AMLS的结构完整性。
This article presents a methodical approach to optimize microstructure (e.g., the crystallographic texture) and topology (e.g., unit cell and struts) concurrently to improve the mechanical properties of additively manufactured metallic lattice structures (AMLS), i.e., yield strength and plastic flow stress. Full-field elastoviscoplastic Fast Fourier Transform (EVP-FFT) crystal plasticity (CP) simulations are employed to determine the optimal microstructure. The CP model parameters were calibrated to measured macroscopic stress-strain response and microstructural data for polycrystalline samples of additively manufactured (AM) Inconel 718 with solution treated and aged (STA) microstructure. Since the crystallographic orientation of the constituent single-crystal grains with respect to the loading direction has a significant impact on the mechanical behavior of the material, stress projection factor analysis was used to determine four candidate textures to explore in for a given unit cell topology. Full-field crystal plasticity simulations were used to determine macroscale yield surface parameters for each of the considered textures, thereby enabling macroscale lattice unit cell simulations that account for the underlying microstructure. The calibrated microstructure-dependent yield surfaces are used to investigate the effect of different microstructures on the mechanical response of different LS topologies with the same relative density. The results show that in a texture with < 111 > crystallographic direction, parallel to the loading direction, the tensile and compressive yield strength are 20% and 58% larger, respectively compared to the AM STA IN718 texture. Furthermore, when this texture is used in conjunction with the Rhoctan topology, the results demonstrate 50% improvement in both the yield strength and modulus of elasticity relative to previously optimized AMLS designs that did not directly account for microstructure. This simultaneous consideration of microstructure and topology during optimization, thus, significantly enhances the structural integrity of the AMLS.