Achieving high strength and superior ductility in Al-Si alloy by cold rolling and friction stir processing
Achieving high strength and superior ductility in Al-Si alloy by cold rolling and friction stir processing
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DOI：
10.1016/j.jallcom.2021.163102
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发表时间：
2021-12-08
影响因子：
6.2
通讯作者：
Jamaati, Roohollah
中科院分区：
文献类型：
--
作者：
Soleymanpour, Mehdi;Aval, Hamed Jamshidi;Jamaati, Roohollah
研究了热处理、轧制和搅拌摩擦加工工艺对亚共晶Al-Si合金显微组织、硬度、拉伸行为和断裂机制的影响。该FSP导致的纵横比的减少，并增加了颗粒的大小和球形度。此外，细小的富硅和富铁颗粒均匀分布在基体中。随着转速的增加，颗粒尺寸和长径比减小，球形度增大。在转速为800 rpm时，获得了最佳形貌的Si颗粒（尺寸为2.23 μ m，纵横比为1.91，球形度为0.682）。FSPed样品的显微硬度分布大致均匀。冷轧后，屈服强度（YS）、极限抗拉强度（UTS）和能量吸收（EA）分别提高到288.7MPa、296.0MPa和18.5J/cm 3，但总延伸率（TE）降低到6%。有趣的是，所有FSP处理的样品的YS、UTS、TE和EA都远高于初始材料。800-120样品具有最好的拉伸性能，其中YS、UTS、TE和EA为116.7 MPa、235 MPa、27.2%和57.9 J/cm 3，分别代表162%、43%、263%和395%的改善。断口分析结果表明，初始试样和热处理试样中的优先裂纹均沿沿着富Al/Si和富Al/Fe界面垂直于加载方向扩展。相比之下，轧制和FSP处理样品的裂纹平面相对于加载方向取向约45度。初始、热处理和轧制样品的断裂以解理模式为主。相比之下，FSP处理的样品显示出完全的韧性断裂。(c)2021爱思唯尔有限公司版权所有。
In the current work, the influence of heat treatment, rolling, and friction stir processing (FSP) on the microstructure, hardness, tensile behavior, and fracture mechanism of hypoeutectic Al-Si alloy were investigated. The FSP led to a reduction in the aspect ratio and increased the size and sphericity of particles. Also, fine silicon and Fe-rich particles were uniformly distributed in the matrix. With increasing the rotational speed, the size and aspect ratio of particles was decreased, and their sphericity was increased. The best morphology of Si particles (size of 2.23 mu m, aspect ratio of 1.91, and sphericity of 0.682) had been obtained at the rotational speed of 800 rpm. The microhardness profiles of the FSPed samples were roughly homogeneous. After the cold rolling, the yield strength (YS), ultimate tensile strength (UTS), and energy absorption (EA) were enhanced to 288.7 MPa, 296.0 MPa, and 18.5 J/cm3, however, the total elongation (TE) was reduced to 6%. Interestingly, the YS, UTS, TE, and EA of all FSPed samples were much higher than that of the initial material. The 800-120 sample had the best tensile properties with YS, UTS, TE, and EA of 116.7 MPa, 235 MPa, 27.2%, and 57.9 J/cm3, representing 162%, 43%, 263%, and 395% improvement, respectively. The results of the fractography exhibited that the preferential cracks propagated perpendicularly to the loading direction along the Al/Si and Al/Fe-rich interfaces in the initial and heat-treated samples. In contrast, the crack planes of the rolled and FSPed samples were oriented around 45 degrees with respect to the loading direction. The fracture of the initial, heat-treated, and rolled samples was dominated by cleavage mode. In contrast, the FSPed samples revealed a full ductile fracture. (c) 2021 Elsevier B.V. All rights reserved.