Abd El-Aty Ali, Xu Yong, Zhang Shi-Hong, Ha Sangyul, Ma Yan, Chen Dayong
Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, PR China.
School of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, PR China.
J Adv Res. 2019 Jan 29;18:19-37. doi: 10.1016/j.jare.2019.01.012. eCollection 2019 Jul.
Since AA2060-T8 was introduced in the past few years, investigating the mechanical response, fracture mechanisms, and anisotropic behaviour of AA2060-T8 sheets under high strain rate deformation has been crucial. Thus, uniaxial tensile tests were performed under quasi-static, intermediate, and high strain rate conditions using universal testing machines as well as split Hopkinson tensile bars. The experimental results showed that the ductility of AA2060-T8 sheets was improved during high strain rate deformation because of the adiabatic softening and the inertia effect which contribute to slow down the necking development, and these results were verified by the fracture morphologies of high strain rate tensile samples. Furthermore, the strain rate hardening influence of AA2060-T8 was significant. Therefore, the Johnson-Cook constitutive model was modified to consider the effects of both strain and strain rates on the strain hardening coefficient. The results obtained from the improved Johnson-Cook constitutive model are in remarkable accordance with those obtained from experimental work. Thus, the improved Johnson-Cook model can predict the flow behavior of AA2060-T8 sheets at room temperature over a wide range of strain rates. The results of the present study can efficiently be used to develop a new manufacturing route based on impact hydroforming technology (IHF) to manufacture sound thin-walled-complex shape components from AA2060-T8 sheets at room temperature.
自从AA2060-T8在过去几年被引入以来，研究AA2060-T8板材在高应变速率变形下的力学响应、断裂机制和各向异性行为至关重要。因此，使用万能试验机以及分离式霍普金森拉伸杆在准静态、中间和高应变速率条件下进行了单轴拉伸试验。实验结果表明，由于绝热软化和惯性效应减缓了颈缩发展，AA2060-T8板材在高应变速率变形过程中的延展性得到了提高，高应变速率拉伸样品的断口形貌验证了这些结果。此外，AA2060-T8的应变速率硬化影响显著。因此，对约翰逊-库克本构模型进行了修正，以考虑应变和应变速率对应变硬化系数的影响。从改进的约翰逊-库克本构模型获得的结果与实验工作获得的结果显著一致。因此，改进的约翰逊-库克模型可以预测AA2060-T8板材在室温下宽范围应变速率内的流动行为。本研究结果可有效地用于开发基于冲击液压成形技术（IHF）的新制造工艺，以在室温下由AA2060-T8板材制造出质量良好的薄壁复杂形状部件。
