Snopiński Przemysław, Donič Tibor, Tański Tomasz, Matus Krzysztof, Hadzima Branislav, Bastovansky Ronald
Department of Engineering Materials and Biomaterials, Silesian University of Technology, 18A Konarskiego Street, 44-100 Gliwice, Poland.
Research Centre of University of Žilina, University of Žilina, 010 26 Žilina, Slovakia.
Materials (Basel). 2021 Feb 20;14(4):1010. doi: 10.3390/ma14041010.
To date, numerous investigations have shown the beneficial effect of ultrasonic vibration-assisted forming technology due to its influence on the forming load, flow stress, friction condition reduction and the increase of the metal forming limit. Although the immediate occurring force and mean stress reduction are known phenomena, the underlying effects of ultrasonic-based material softening remain an object of current research. Therefore, in this article, we investigate the effect of upsetting with and without the ultrasonic vibrations (USV) on the evolution of the microstructure, stress relaxation and hardness of the AlMg3 aluminum alloy. To understand the process physics, after the UAC (ultrasonic assisted compression), the microstructures of the samples were analyzed by light and electron microscopy, including the orientation imaging via electron backscatter diffraction. According to the test result, it is found that ultrasonic vibration can reduce flow stress during the ultrasonic-assisted compression (UAC) process for the investigated aluminum-magnesium alloy due to the acoustic softening effect. By comparing the microstructures of samples compressed with and without simultaneous application of ultrasonic vibrations, the enhanced shear banding and grain rotation were found to be responsible for grain refinement enhancement. The coupled action of the ultrasonic vibrations and plastic deformation decreased the grains of AlMg3 alloy from ~270 μm to ~1.52 μm, which has resulted in a hardness enhancement of UAC processed sample to about 117 HV.
迄今为止，大量研究表明超声振动辅助成型技术具有有益效果，这归因于其对成型载荷、流变应力、摩擦条件的降低以及金属成型极限的提高所产生的影响。尽管即时出现的力和平均应力降低是已知现象，但基于超声的材料软化的潜在影响仍是当前研究的对象。因此，在本文中，我们研究了有无超声振动（USV）镦粗对AlMg3铝合金微观结构演变、应力松弛和硬度的影响。为了理解过程物理，在超声辅助压缩（UAC）之后，通过光学和电子显微镜对样品的微观结构进行了分析，包括通过电子背散射衍射进行取向成像。根据测试结果，发现由于声学软化效应，在超声辅助压缩（UAC）过程中，超声振动可以降低所研究的铝镁合金的流变应力。通过比较在有和没有同时施加超声振动的情况下压缩的样品的微观结构，发现增强的剪切带和晶粒旋转是晶粒细化增强的原因。超声振动和塑性变形的耦合作用使AlMg3合金的晶粒从约270μm减小到约1.52μm，这导致UAC处理样品的硬度提高到约117 HV。
