利用纳米硬度试验法确定Cr/Cu梯度材料的变形特性

Nanoindentation of Cr/Cu Functionally Graded Thin Films on Cu Substrates

利用纳米硬度仪研究了在Cu基底上的Cu／Cr梯度膜的机械性能。梯度膜是通过将Cu靶和Cr靶同时溅射到Cu基底材料上,但两个靶的相对溅射功率随溅射时间变化而制备。利用Oliver and Pharr方法得到了膜随其厚度变化的硬度和弹性模量。然后利用加载／卸载／再加载的方法得到了在不同深度(即膜的厚度)压头平均压力与相对压入深度之间的关系曲线,在此曲线上可以明显反映出材料的屈服特性。

Hardness, elastic modulus and elasto-plastic deformation curves of a Cr/Cu functionally graded thin films on Cu substrates were investigated by nano-indentation experiments. Thin films are prepared by sputter deposition with Cr and Cu targets at room temperature. Hardness and elastic modulus dependence on the thickness of the thin film were obtained based on the Oliver and Pharr method. Deformation curves of the thin film, including elastic deformation portion and plastic deformation portion at a point loading have been determined. It is found that such deformation curves, and the hardness and elastic modulus dependence on the penetration depth of indenter, can be strongly correlated with variations of the composition and mechanical properties of the thin film with the thickness.