发表机构
The Pennsylvania State University; The Ohio State University（宾夕法尼亚州立大学; 俄亥俄州立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对Al/Cu接头脆性金属间化合物问题，提出Ag中间层策略，结合CALPHAD、第一性原理和实验验证，使接头强度从47.9提升至67.4 MPa，建立了理性选择中间层的可迁移工作流。
AI 中文摘要
异种Al/Cu接头对电池组装配至关重要；然而，其机械强度受到脆性Al-Cu金属间化合物（IMCs）如Al2Cu和Al4Cu9的限制。抑制这些相的中间层策略在很大程度上仍停留在经验层面，缺乏将中间层化学与所形成的相及其固有力学特性联系起来的预测框架。本文引入Ag中间层，并将计算热力学、第一性原理计算、微观结构表征和力学测试结合成对接头的单一自洽描述。CALPHAD（相图计算）平衡和Scheil模拟预测了富Al的Al-Ag熔合区的凝固路径，并解释了当Ag存在时Cu掺入受限的原因；能量色散X射线光谱（EDS）和电子背散射衍射（EBSD）确认FCC Al-Ag固溶体为主要组成相。在准谐近似下的第一性原理声子计算得到了有限温度熵和吉布斯能，并以CALPHAD为基准进行验证，而弹性常数通过Pugh准则（即体模量/剪切模量（B/G）比）评估延展性。所有Al-Ag相，包括观察到的固溶体，均超过Pugh阈值1.75，而目标Al-Cu IMCs则未达到，这为中间层的有效性提供了机理基础。这种微观结构变化转化为性能提升：名义强度从47.9 MPa提高到67.4 MPa。纳米压痕测得熔合区约化模量为82.8 GPa（杨氏模量82.0 GPa），而计算的0 K Voigt-Reuss-Hill值为71.4 GPa。本研究建立了可迁移的CALPHAD、第一性原理和实验工作流程，用于异种金属连接中合理的中间层选择。
英文摘要
Dissimilar Al/Cu joints are essential to battery-pack assemblies; however, their mechanical strength is limited by brittle Al-Cu intermetallic compounds (IMCs) such as Al2Cu and Al4Cu9. Interlayer strategies to suppress these phases remain largely empirical, lacking a predictive framework linking interlayer chemistry to the phases that form and to their intrinsic mechanical character. Here an Ag interlayer is introduced and combines computational thermodynamics, first-principles calculations, microstructural characterization, and mechanical testing into a single self-consistent description of the joint. CALculation of PHAse Diagrams (CALPHAD) equilibrium and Scheil simulations predict the solidification path of the Al-rich Al-Ag fusion zone and explain why Cu incorporation is limited when Ag is present; energy-dispersive X-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD) confirm an FCC Al-Ag solid solution as the dominant constituent. First-principles phonon calculations within the quasiharmonic approximation yield finite-temperature entropy and Gibbs energy, benchmarked against CALPHAD, while elastic constants assess ductility via the Pugh criterion (i.e., the bulk/shear (B/G) modulus ratio). All Al-Ag phases, including the observed solid solution, exceed the Pugh threshold of 1.75, whereas the targeted Al-Cu IMCs do not, giving a mechanistic basis for the interlayer's effectiveness. This microstructural change translates into improved performance: nominal strength rises from 47.9 to 67.4 MPa. Nanoindentation gives a fusion-zone reduced modulus of 82.8 GPa (Young's modulus 82.0 GPa), versus a calculated 0 K Voigt-Reuss-Hill value of 71.4 GPa. The present work establishes a transferable CALPHAD, first-principles, and experiment workflow for rational interlayer selection in dissimilar-metal joining.
Comments31 pages, 13 figures and 1 table
