The microstructure and mechanical behavior of ultra-fine grained (UFG) 5083 aluminum alloy fabricated by mechanical milling and hot isostatic pressed (HIP) followed by hot extrusion. The chemical composition, density, hardness and tensile property of the UFG 5083Al alloy were also characterized. The results show that the samples show an average grain size of 322 nm. The yield stress, ultimate tensile stress and tensile strain-to-failure are 560 MPa, 566MPa and 6.3%, respectively. The fractographic observations of the as-extruded 5083 alloy demonstrate a feature of microvoid accumulation fracture. Semi-quantitative analysis suggest that the strengthening mechanisms including grain boundaries strengthening, dispersion strengthening, solid-solution strengthening and dislocation strengthening are the dominant strengthening mechanisms. A calculation shows that the grain boundaries strengthening and dispersion strengthening are the dominant strengthening mechanisms.%采用室温机械球磨、热等静压和热挤压工艺制备超细晶5083铝合金,利用X射线衍射(XRD)、透射电镜(TEM)对材料的显微组织进行分析和观察,并对所制备材料的化学成分、密度、硬度和拉伸性能进行测定,在理论分析的基础上,半定量估算各种强化机制对材料强度的贡献.结果表明:制备的超细晶5083铝合金的平均晶粒尺寸为322 nm,相对密度为99.72%,屈服强度和抗拉强度分别为560 MPa和566 MPa,断后伸长率为6.3%;断裂方式为微孔聚集型断裂;强化机制包括细晶强化、弥散强化、固溶强化、位错强化,其中以细晶强化和弥散强化的贡献最大.
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