5083铝合金表面化学镀Ni-P镀层的力学性能

采用化学镀方法在5083铝合金基体上制备了Ni-P非晶薄膜,采用纳米压痕技术在不同应变速率下研究Ni-P非晶薄膜的硬度、弹性模量和变形行为.结果表明,Ni-P非晶薄膜硬度不是一个恒定值,与纳米压痕的压入深度有关,而弹性模量基本保持不变;载荷-深度曲线出现跳跃及台阶现象与应变速率有关,应变速率愈慢,曲线出现台阶现象越明显;跳跃台阶源于单个剪切带的开动,而在高的应变速率条件下,由于多个剪切带的开动,曲线上便不出现跳跃台阶.

Mechanical Properties of Ni-P Coatings Prepared by Electroless Plating on Surface of 5083 Aluminum Alloy

Amorphous Ni-P films were prepared on 5083 aluminum alloy substrates by electroless plating. The mechanical properties of Ni-P films with different strain rates were investigated by nanoindentation tests. It was found that the hardness of Ni-P films is not constant， which depends on depth. Elastic modulus is almost invariable. Discrete displacement bursts and jumping steps in load-depth curves are associated with the loading-rate. The slower the loading rate is， the more obvious the curve steps appear. The discrete displacement burst starts from a single shear band. In a high strain rate， jumping steps do not appear on curves.