The effect of alloying elements on the ductility of Al-Mg-Si alloys
The effect of alloying elements on the ductility of Al-Mg-Si alloys
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DOI：
10.1016/j.msea.2017.03.078
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发表时间：
2017-05
期刊：
影响因子：
6.4
通讯作者：
Magnus Sætersdal Remøe;K. Marthinsen;I. Westermann;K. Pedersen;J. Røyset;C. Marioara
中科院分区：
文献类型：
--
作者：
Magnus Sætersdal Remøe;K. Marthinsen;I. Westermann;K. Pedersen;J. Røyset;C. Marioara
进行实验以记录不同合金元素对挤压 Al-Mg-Si 合金的微观结构和相关应力应变行为的综合影响，特别强调延展性和断裂特性。选择了四种具有不同浓度和相对含量的 Mg、Si、Fe、Cu 和 Mn 的合金进行检查。为了准确描述强度-延展性关系，使用激光引伸计进行拉伸测试，并进行扫描 (SEM) 和透射显微镜 (TEM) 研究，将微观结构和断裂特征与应力-应变行为关联起来。研究发现，在不存在其他合金元素的情况下，过量的 Si（Mg/Si<1.73）会对 Al-Mg-Si 合金的延展性产生不利影响，导致部分晶间断裂。这与游离硅在晶界偏析、形成粗大硅颗粒以及固溶热处理期间形成 Mg2Si 颗粒有关。添加 Fe 和 Cu 提高了延展性和强度，这可能是由于较低的固溶线温度和增加的初级颗粒形成，导致晶界脆化的游离 Si 减少。通过引入 Mn 发现了最高的延展性，Mn 除了将游离 Si 束缚到第二相颗粒外，还通过形成弥散体抑制了再结晶。添加了 Mn 和 Cu 的过量镁合金 (Mg/Si>1.73) 具有最理想的抗拉强度和延展性组合。
Experiments were conducted to document the combined effect of different alloying elements on the microstructure and associated stress-strain behavior of extruded Al-Mg-Si alloys, with a special emphasis on the ductility to fracture characteristics. Four alloys with different concentrations and relative amounts of Mg, Si, Fe, Cu, and Mn were selected for examination. In order to obtain an accurate description of the strength-ductility relationship, tensile testing was performed with a laser extensometer, and scanning (SEM) and transmission microscope (TEM) studies were carried out to correlate the microstructure and fracture characteristics with the stress-strain behavior. Excess-Si (Mg/Si<1.73) was found to have a detrimental effect on the ductility of Al-Mg-Si alloys without the presence of additional alloying elements, leading to fracture occurring partly intergranularly. This was linked to the segregation of free Si at grain boundaries, forming coarse Si-particles, and the formation of Mg2Si particles during solution heat treatment. Adding Fe and Cu improved the ductility and strength, which could be attributed to a lower solvus temperature and increased formation of primary particles, resulting in less free Si for embrittlement of grain boundaries. The highest ductility was found by introducing Mn, which in addition to tie up free Si to second-phase particles, suppressed recrystallization by forming dispersoids. The most desirable combination of tensile strength and ductility was found in an excess-Mg alloy (Mg/Si>1.73) with additions of both Mn and Cu.