高强高导Cu-Nb微观复合材料的尺寸效应

Size Effect on high strength and high conductivity Cu-Nb microcomposites

摘要:

高强度高电导Cu-Nb微观复合材料具有纳米结构的Nb芯丝和纯Cu层，材料的尺寸效应促使力学性能呈规律变化。 本文通过不同线材尺寸的应力应变曲线测试研究了材料强度随内部Nb芯丝尺寸的变化规律，通过纳米压痕手段分析了材料弹性模量和纳米压痕值随随材料尺寸的变化特征。结果表明，材料的强度实测值远大于混合定律计算的理论值，且随Nb芯丝尺寸的减小强度呈指数增加，Nb芯丝纳米硬度值也随尺寸的减小显著增加。与电子自由程相关的界面电子散射作用是影响材料电导的主要因素。

Abstract:

High strength and high conductivity Cu-Nb microcomposites are with nano-structured Nb fibers and pure Cu matrix. Strength size effect has been observed. The rule of strength changing with the size of Nb filaments was analyzed by stress-strain curves. The characteristics of elastic modulus and nano-indention hardness varying with the thickness of Nb filaments are investigated by nanoindentation. It is shown that the measured value of strength is considerably higher than that obtained by ROM and the UTS of Cu-Nb increases exponentially with the decreasing of dNb. Moreover, the nano-indention hardness of Nb filaments also increases greatly as the size dreased. It is believed that electronic interface scattering associated with the mean free path of the electrons is the main factor of Cu-Nb conductivity.