钛合金表面电镀纳米镍层厚度的优化设计

在Ti6Al4V合金表面电镀适当厚度的纳米纯镍,是提高其表面强度和耐磨性的一种行之有效的方法.作为一种整体结构件,在实际应用中镍硬化层的厚度对部件的内应力分布以及尺寸稳定性有着重要的影响.为确定钛合金表面镍硬化层的合适厚度,利用纳米显微力学探针测量了材料的弹性模量,采用ANSYS有限元软件,对钛合金表面电镀纳米镍硬化层在受压情况下的应力分布进行了分析,并以此对纳米镍硬化层的厚度进行了模拟设计.研究表明:当电镀纳米镍硬化层厚度在0.25～1.25 mm范围时,最大等效应力发生在钛合金和镍之间,容易引起界面处裂纹的产生;合适的电镀纳米镍硬化层厚度范围应在1.25～2.5 mm,最佳厚度约为2 mm.

Optimization and design of thickness of nano nickel-plate hardened layer on titanium alloy surface

A layer of nano Ni can be plated to the surface of Ti6Al4V alloy, which is one of the effective ways to improve the surface intensity and wearability of the titanium alloy-based parts. Being a kind of integrated structural parts, different thickness of Ni hardened layer has great effect on distribution of internal stress and dimensional stability. In addition to get suitable thickness of Ni layer, material elastic modulus was measured by Nano Indenter II, then the stress distribution of the hardened layer of Nano Nickel-plate was analyzed under press stress by FEM simulation, so that the thickness of the hanrdened layer was optimize and designed. The results showed that the maximal equivalent stress was located interface of titanium alloy and Ni when the hardened Layer thickness was 0. 25 - 1.25 mm, which was easy to generate crack; the suitable range of hardened layer thickness was 1.25 -2.5mm, the optimal thickness was about 2 mm.