多晶铜膜纳米压入蠕变性能

Mechanisms of polycrystalline Cu thin films during nanoindentation creep

在JGP560V磁控溅射镀膜设备上镀制多晶铜膜,利用纳米压入技术测量了其室温下的蠕变性能。结果表明:由于不同加载方式下,材料加工硬化程度的不同造成了应力指数的差异,因而,不同加载方式对测得的铜膜蠕变应力指数有比较大的影响;由于材料在高载荷时在压头下端产生更多的位错,阻碍了压头的压入,使蠕变率降低,因而,随着保载载荷的升高,蠕变应力指数变大。

Two creep experiments were conducted on polycrystalline Cu thin films with nanoindentation instrument. The thin films were deposited by magnetron sputtering technique. The results show that the loading modes have great effect on the nanoindentation creep properties. The changes of stress exponent depend on the rate of work hardening under different loading conditions. And with increasing holding load, the stress exponents increase under both two loading modes because of many accumulated dislocations under the indenter tip, which reduces the creep rate for the indenter and makes it difficult to penetrate further.