摘要
Pure aluminum samples were processed by equal channel angular pressing（ECAP） up to 10 passes at room temperature. The effects of the ECAP number of passes on the microstructure evolution, the mechanical properties, deformation homogeneity and corrosion behavior of the processed samples were fully investigated. The imposed strain resulted in an obvious reduction in the grain size from 390 μm before ECAP down to 1.8, 0.4, and 0.3 μm after ECAP up to 2, 4 and 10 passes, respectively. The microhardness, deformation homogeneity and tensile strength were increased while the elongation decreased with the increase of ECAP number of passes. Immersion tests, open circuit potential, Tafel polarization, cyclic polarization and potentiostatic measurements in 3.5% Na Cl solution revealed an obvious improvement in the corrosion resistance of ECAP processed samples compared with the as-cast sample. The increase of the number of passes can be used successfully in producing ultra-fine grained（UFG） bulk pure aluminum sample with a high misorientation angle, reasonably high mechanical properties and corrosion resistance.
在室温下,采用等径角挤压法加工纯铝样品10道次。研究等径角挤压道次数对加工样品显微组织演变、力学性能、变形均匀性和腐蚀行为的影响。所施加的应变导致晶粒尺寸明显减小,等径角挤压前,晶粒尺寸为390μm,经等径角挤压2、4和10道次后,晶粒尺寸分别减小至1.8、0.4和0.3μm。随着等径角挤压道次数的增加,显微硬度、变形均匀性和拉伸强度增大,而伸长率下降。浸泡试验、开路电势、Tafel极化、循环极化和恒电位测试表明,与铸态样品相比,在3.5%Na Cl溶液中,经等径角挤压样品的耐蚀性明显提高。增加挤压道次数能成功用来生产具有高错位角、高力学性能和耐蚀性的超细晶大块纯铝。
