纳米晶Al的制备及拉伸性能(Ⅱ)

SYNTHESIS AND TENSILE PROPERTIES OF NANOCRYSTALLINE Al(Ⅱ)

将用蒸发法制备的纳米Al粉体冷压成直径25×2mm的块材经620℃／40min热处理后，进行变形量为55％的冷轧形变处理线切割成标距为10mm的拉伸试样.冷轧后样品的相对密度为99％，平均晶粒尺寸约为53nm．拉伸实验结果表明：冷变形致密化的纳米晶Al的屈服强度σ0．2和断裂强度σb分别是同质粗晶Al的12～16倍和5～6倍：延伸率δ比同质冷轧粗晶Al提高大约28％。

Nano-Al particfes prepared by plasma evaporation method were compacted at room temperature into disc-shape samples with a dimension of 25×2mm. After annealing at 620℃ for 40min, the samples were cold-rolled to form sheets with thickness of lmm and length of 40mm. The sheets were machined into dogbone-like samples for tensile test. Densities of the sampfes are all 99%of theoretical density. Average grain size determined by XRD and TEM observation is about 53nm.The results of uniaxial tensile test showeds yield strength 0.2 and breaking strength of nano-Al densified by cold deformation are 12-16 and 5-6 times that of annealed coarse-grained Al, respectively.Its elongation b is about 28% greater than that of cold-rolfed coarse-grained Al and 2 times that of undeformed nano-Al.The efFects of cold deformation on the properties of nano-Al were discussed.