Wang Haiyang, Wang Chuanjie, Zhang Linfu, Chen Gang, Zhu Qiang, Zhang Peng
Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Harbin Institute of Technology, Ministry of Education, Harbin 150080, China.
School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209, China.
Materials (Basel). 2021 Nov 12;14(22):6846. doi: 10.3390/ma14226846.
The performance of clad foils in microforming deserves to be studied extensively, where the strain rate sensitivity of the clad foil concerning the forming performance is a crucial factor. In this paper, the strain rate sensitivity of the mechanical properties of coarse-grained (CG) Cu/Ni clad foils in the quasi-static strain rate range (ε˙=10-4 s-110-1 s-1) is explored by uniaxial tensile tests under different strain rates. The results show that the strength and ductility increase with strain rate, and the strain rate sensitivity value is in the range of 0.0120.015, which is three times the value of m for CG pure Cu. The fracture morphology shows that slip bands with different directions are entangled in localized areas near the interface layer. Molecular dynamics simulations demonstrate the formation of many edged dislocations at the Cu/Ni clad foils interface due to a mismatch interface. The improved ductility and strain rate sensitivity is attributed to the interaction and plugging of the edged dislocations with high density in the interface layer. Additionally, the influence of size effect on mechanical properties is consistently present in the quasi-static strain rate range. This paper helps to understand the strain rate sensitivity of CG clad foils and to develop clad foils in microforming processes.
复合箔材在微成形中的性能值得深入研究，其中复合箔材的应变速率敏感性对成形性能而言是一个关键因素。本文通过在不同应变速率下的单轴拉伸试验，探究了粗晶（CG）铜/镍复合箔材在准静态应变速率范围（ε˙ = 10⁻⁴ s⁻¹10⁻¹ s⁻¹）内力学性能的应变速率敏感性。结果表明，强度和延展性随应变速率增加，应变速率敏感值在0.0120.015范围内，是粗晶纯铜m值的三倍。断口形貌显示，不同方向的滑移带在界面层附近的局部区域相互缠结。分子动力学模拟表明，由于界面失配，在铜/镍复合箔材界面处形成了许多刃型位错。延展性和应变速率敏感性的提高归因于界面层中高密度刃型位错的相互作用和塞积。此外，在准静态应变速率范围内，尺寸效应始终对力学性能存在影响。本文有助于理解粗晶复合箔材的应变速率敏感性，并推动微成形工艺中复合箔材的发展。
