Jurczak Wojciech, Trzepieciński Tomasz, Kubit Andrzej, Bochnowski Wojciech
Mechanical and Electrical Engineering Department, Polish Naval Academy, 81-103 Gdynia, Poland.
Department of Manufacturing and Production Engineering, Rzeszow University of Technology, al. Powst. Warszawy 8, 35-959 Rzeszów, Poland.
Materials (Basel). 2022 Jan 29;15(3):1066. doi: 10.3390/ma15031066.
The aim of this study is to determine the influence of the amount of magnesium in Al-Mg alloys and strain rate on the grain refinement and mechanical properties of the material as determined in a dynamic tensile test. Hydrostatic extrusion was used to process the material. This method is not commonly used to impose severe plastic deformation of Al-Mg alloys. The article presents the results of static and dynamic strength tests on aluminium alloys subjected to plastic deformation in the hydrostatic extrusion process. Technically pure aluminium Al99.5 and three aluminium alloys with different magnesium content, Al-1Mg, Al-3Mg and Al-7.5Mg, were used in the tests. The samples were subjected to static tests using the uniaxial tensile test machine and dynamic tests using a rotary hammer. Compared to pure aluminium, increasing the magnesium content in Al-based alloys strengthened them in hydrostatic extrusion (logarithmic strain ε = 0.86) and caused an increase in the static ultimate tensile stress R, relative strain ε and the value of the yield stress. For strengthened aluminium alloys, an increase in the strain rate from 750 to 1750 s caused an increase in the dynamic ultimate tensile stress from 1.2 to 1.9 times in relation to the static ultimate tensile stress. The increase in magnesium content results in the formation of a larger strengthening phase, influences a different state of stress during dynamic loading and leads to a change in the orientation of the fracture surface. It was also found that an increase in magnesium content is associated with an increased number of voids, which is also directly proportional to the strain rate in the dynamic rotary hammer test.
本研究的目的是确定Al-Mg合金中镁含量和应变速率对材料晶粒细化和力学性能的影响，这些影响通过动态拉伸试验来测定。采用静液挤压工艺对材料进行加工。这种方法通常不用于对Al-Mg合金施加严重塑性变形。本文介绍了在静液挤压过程中经历塑性变形的铝合金的静态和动态强度试验结果。试验中使用了工业纯铝Al99.5以及三种不同镁含量的铝合金，即Al-1Mg、Al-3Mg和Al-7.5Mg。样品使用单轴拉伸试验机进行静态试验，并使用旋转锤进行动态试验。与纯铝相比，在静液挤压（对数应变ε = 0.86）过程中，增加Al基合金中的镁含量会强化合金，并导致静态极限拉伸应力R、相对应变ε和屈服应力值增加。对于强化铝合金，应变速率从750 s增加到1750 s会使动态极限拉伸应力相对于静态极限拉伸应力增加1.2至1.9倍。镁含量的增加会导致形成更大的强化相，影响动态加载过程中的不同应力状态，并导致断裂表面取向发生变化。还发现，镁含量的增加与孔隙数量的增加有关，孔隙数量在动态旋转锤试验中也与应变速率成正比。
