Liu Shiyuan, Xu Hong, Zhang Baohong, Zhang Guowei, Bai Long, Song Heqian, Zhang Dan, Chang Chao, Yu Huan, Yang Chenglong
College of Materials Science and Engineering, North University of China, Taiyuan 030051, China.
Shanxi Provincial Key Laboratory for Controlled Metal Solidification and Precision Manufacturing, Taiyuan 030051, China.
Materials (Basel). 2023 Aug 4;16(15):5469. doi: 10.3390/ma16155469.
Al/Fe bimetals prepared by a compound casting method, combining the excellent properties of both the Al alloy and the ductile cast iron, exhibit great potential for application in achieving engine weight reduction. However, the problem of insufficient interfacial bonding ability because of the difference in thermophysical properties of Al and Fe is particularly prominent. Therefore, in this work, the electrodeposited Cu coating on the surface of the Fe matrix was used as the interlayer of Al/Fe bimetal fabricated by coupling hot-dipping with compound casting to solve the above problem. The effect of Cu interlayer thickness on the interfacial microstructure and shear strength of bimetal was investigated. The experimental results showed that the shear strength up to 77.65 MPa in regard to Al/Fe bimetal with a 5 μm Cu interlayer was obtained. No Cu element was detected at the interface of bimetal regardless of the thickness of the Cu interlayer. The diffusion behavior of the Cu atom at the interface and the influence of the Cu layer at the atomic scale on diffusion reaction and the Al/Fe interface were further revealed by combining first-principle and molecular dynamics calculations. The simulation results revealed that the Cu layer gradually dissolved into an Al alloy at 750 °C, thereby promoting the diffusion reaction of the Al/Fe interface. Meanwhile, the protective role of the Cu layer against oxidation on the surface of the Fe matrix was confirmed. As a result, the interfacial bonding performance was enhanced when the Cu interlayer was introduced.
通过复合铸造法制备的铝/铁双金属结合了铝合金和球墨铸铁的优异性能，在实现发动机减重方面具有巨大的应用潜力。然而，由于铝和铁热物理性能的差异，界面结合能力不足的问题尤为突出。因此，在本工作中，将铁基体表面电沉积的铜涂层用作通过热浸与复合铸造相结合制备的铝/铁双金属的中间层，以解决上述问题。研究了铜中间层厚度对双金属界面微观结构和剪切强度的影响。实验结果表明，对于具有5μm铜中间层的铝/铁双金属，其剪切强度达到了77.65MPa。无论铜中间层的厚度如何，在双金属界面均未检测到铜元素。通过结合第一性原理和分子动力学计算，进一步揭示了铜原子在界面处的扩散行为以及铜层在原子尺度上对扩散反应和铝/铁界面的影响。模拟结果表明，在750℃时铜层逐渐溶解到铝合金中，从而促进了铝/铁界面的扩散反应。同时，证实了铜层对铁基体表面氧化的保护作用。结果，引入铜中间层后，界面结合性能得到了增强。
