电沉积ZrO2/Ni纳米复合材料低温高应变速率超塑性的研究

Research on Low Temperature and High Strain Rate Superplasticity of ZrO_2/Ni Nanocomposite Produced by Electrodeposition

采用电沉积方法制备了平均晶粒尺寸为45nm的ZrO2/Ni复合材料,并通过拉伸和胀形试验对该材料的超塑性能进行了研究。拉伸试验结果表明：材料在温度为420-500℃,应变速率为8.33×10^-4s^-1 -1.67×10^-2s^-1时均获得了高于200%的延伸率。在温度为450℃和应变速率为1.67×10^-3s^-1时,得到最大延伸率605%。用扫描电镜SEM对拉伸前后试件的显微组织进行了观察,发现晶粒在温度的作用下明显长大。采用内径5 mm的凹模对ZrO2/Ni复合材料进行超塑胀形试验,在温度为420-500℃获得高径比H/d高于0.5的胀形件,说明该材料具有良好的超塑性能。

Superplasticity of ZrO2/Ni nanocomposite with a mean grain size of 45nm produced by pulse electrodeposition was investigated under the tensile test and bulging test. The elongation values obtained by tensile test at temperatures ranging from 420℃ to 500℃ and strain rates ranging from 8.33 × 10^-4s^-1 to 1.67 × 10^-2s^-1 are larger than 200%. A maximum elongation of 605% was obtained at a temperature of 450℃ and a strain rate of 1.67 × 10^-3s^-1. SEM was used to observe the microstruetures of the samples before and after tensile test. The results indicate that grain growth occurs obviously by the effect of temperature. Superplastie bulging tests were subsequently performed using dies with diameters of 5mm. The values of H/d exceed 0.5 at temperatures ranging from 420℃ to 500℃ , indicating the good superplasticity of ZrO2/ Ni nanocomposite.