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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。
Pure aluminum samples were machined 10 times at room temperature using an isometric angle extrusion method. The influence of the number of equal-angle squeeze passes on the microstructure evolution, mechanical properties, deformation uniformity and corrosion behavior of the machined samples was investigated. The strain applied resulted in a significant decrease of the grain size. The grain size was 390 μm before equiaxed angle extrusion. After the grain size was reduced to 1.8, 0.4 And 0.3 μm. With the increase of the number of equal angle angular pressing passes, the microhardness, the deformation uniformity and the tensile strength increase, while the elongation decreases. Immersion tests, open circuit potentials, Tafel polarizations, cyclic polarizations and potentiostatic tests showed that the corrosion resistance of samples extruded with isobaric angle was significantly improved in 3.5% NaCl solution compared with as-cast samples. Increasing the number of extrusion passes can be successfully used to produce ultrafine-grained, bulk aluminum with high misalignment angles, high mechanical properties and corrosion resistance.