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为研究调制周期和界面结构对纳米多层膜应变率敏感性的影响,采用电子束蒸发镀膜技术在Si基片上制备了不同周期(Λ=4 nm,12 nm,20 nm)的Cu/Ni纳米多层膜,采用磁控溅射技术在Si基片上制备了不同周期(Λ=5 nm,10 nm,20 nm)的Cu/Nb纳米多层膜。在真空条件下,对Cu/Ni纳米多层膜进行了温度分别为200和400℃、时间4 h的退火处理,对Cu/Nb纳米多层膜进行了温度分别为200、400和600℃,时间为4 h的退火处理。采用XRD和TEM表征了Cu/Ni和Cu/Nb纳米多层膜的结构,采用纳米压痕仪获取了不同加载应变率(0.005、0.01、0.05和0.2 s~(-1))下纳米多层膜的硬度。结果表明,应变率敏感性受到界面结构和晶粒尺寸的影响,非共格界面密度提高以及晶粒尺寸变大均可导致应变率敏感性下降。当周期变大时,Cu/Ni纳米多层膜的非共格界面密度提高,晶粒尺寸变大,应变率敏感性指数m减小;当周期变大时,Cu/Nb纳米多层膜的非共格界面密度下降,晶粒尺寸变大,m基本不变。随退火温度上升,Cu/Ni和Cu/Nb纳米多层膜应变率敏感性大体上呈现下降趋势,这是由退火过程中非共格界面密度上升和晶粒长大共同引起的。
In order to study the effect of modulation period and interface structure on the strain rate sensitivity of nanocomposite films, Cu / Ni nanostructures with different periods (Λ = 4 nm, 12 nm, 20 nm) were prepared on Si substrate by electron beam evaporation Multilayer Cu / Nb multilayered films with different periods (Λ = 5 nm, 10 nm, 20 nm) were prepared on Si substrates by magnetron sputtering. Under vacuum condition, the Cu / Ni nano-multilayer films were annealed at 200 and 400 ℃ for 4 h, and the Cu / Nb nano-multilayer films were annealed at 200, 400 and 600 ℃, Time 4 h annealing treatment. The structure of Cu / Ni and Cu / Nb nano-multilayers were characterized by XRD and TEM. The nano-multilayers with different loading strains (0.005, 0.01, 0.05 and 0.2 s -1) Film hardness. The results show that the sensitivity of strain rate is affected by the interface structure and grain size, and the increase of non-coherent interfacial density and grain size can lead to the decrease of strain rate sensitivity. When the period becomes larger, the density of non-coherent interface of Cu / Ni nano-multilayer films increases and the grain size becomes larger and the strain rate sensitivity index m decreases. When the period increases, the Cu / Nb nano- Non-coherent interface density decreased, grain size becomes larger, m basically unchanged. With the increase of annealing temperature, the strain rate sensitivity of Cu / Ni and Cu / Nb nano-multilayers generally shows a downward trend, which is caused by the increase of density of non-coherent interface and the grain growth during annealing.