Mechanical Properties of Bulk Ultrafine Grained Aluminum Fabricated by Torsion Deformation at Various Temperatures and Strain Rates
Mechanical Properties of Bulk Ultrafine Grained Aluminum Fabricated by Torsion Deformation at Various Temperatures and Strain Rates
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DOI：
10.2320/matertrans.ma201321
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发表时间：
2014
影响因子：
1.2
通讯作者：
S. Khamsuk;N. Park;Si-feng Gao;D. Terada;H. Adachi;N. Tsuji
中科院分区：
文献类型：
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作者：
S. Khamsuk;N. Park;Si-feng Gao;D. Terada;H. Adachi;N. Tsuji
通过扭转变形，在不同温度和应变速率下将商业纯铝严重变形至等效应变 4，以产生具有各种超细晶粒 (UFG) 微观结构的样本。通过电子背散射衍射（EBSD）和透射电子显微镜（TEM）对微观结构进行了表征。微观结构观察表明，扭转变形样品具有不同的平均晶粒尺寸，范围为0.38至8.6μm。微观结构中的晶粒尺寸和位错密度取决于 ZenerHollomon 参数组织的变形条件。通过室温拉伸试验研究扭转变形试件的力学性能。结果发现，超细晶粒样品表现出高强度，几乎达到了原材料强度的三倍。 UFG 铝的强度高于传统粗晶铝的 Hall Petch 关系所预期的水平。 UFG 铝材的强化机制根据扭转变形过程中引入的子结构进行了讨论。 [doi:10.2320/matertrans.MA201321]
A commercial purity aluminum was heavily deformed up to an equivalent strain of 4 at various temperatures and strain rates by torsion deformation to produce specimens with various ultrafine grained (UFG) microstructures. The microstructures were characterized by electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The microstructural observation revealed that the torsion deformed specimens had various mean grain sizes ranging from 0.38 to 8.6 μm. The grain size and dislocation density in the microstructures depended on the deformation conditions organized by ZenerHollomon parameter. The mechanical properties of the torsion deformed specimens were investigated by tensile test at room temperature. It was found that the ultrafine grained specimens showed high strength which reached a value almost three times higher than that of the starting material. The strength of the UFG aluminum was higher than the level expected from the Hall Petch relationship for conventionally coarse grained aluminum. The strengthening mechanisms in the UFG aluminum were discussed in terms of substructures introduced during torsion deformation. [doi:10.2320/matertrans.MA201321]