Development of Evaluation System of Mechanical Properties of Multi-Thin Layrs by Ultra-Micro Indentation Test

(1)开发了多层薄层上三角锥体压痕的弹塑性有限元分析软件。(2)利用超微压痕试验机对涂层的杨氏模数进行了评价。利用卸荷过程中荷载与侵彻强度之间的关系来确定土体的弹性模量。在逐渐减小极限载荷的情况下进行压痕试验，以确定基板材料不再对变形产生影响的点。在这一点之后，卸荷是涂层模数和压头的几何形状的函数。(3)在用超微压痕试验机测量薄膜的杨氏模数时，加载/卸载速度较慢，容易高估系统外部的蠕变变形和/或振动引起的杨氏模数。(4)利用原子力显微镜超微硬度计对钨(001)单晶进行了纳米压痕测量。对于电解抛光的钨单晶，在压痕过程中会发生突然穿透现象。机械抛光的表面不会出现这种情况。得到的载荷与侵彻强度之间的关系与电解抛光钨单晶突然侵彻前的弹性有限元分析结果吻合较好。因此，电解抛光的钨单晶很有可能被用作原子力显微镜超微硬度测试的标准材料。

(1) Software for elastic-plastic FEM analysis of a triangular pyramidal indentation on a multi-thin layrs is developed.(2) An 'ultra-micro indentation tester' is used to evaluate the Young's modulus of thin coatings. The relationship between the load and the penetration during unloading is used to determined the modulus. Indentation tests at gradually reducing ultimate load are carried out to determine the point at which the substrate material no longer has an influence on the deformation. After this point the unloading is a function of the coating modulus and the geometry of the indenter alone. This method is named the extrapolation method.(3) In the evaluation of Young's modulus of thin coatings by ultra-micro indentation tester, slow loading/unloading velocity tends to make ones overestimate the modulus due to creep deformation and/or vibrations from the outside of the system.(4) Nanoindentation measurement for tungsten (001) single crystal is conducted with an AFM ultra-micro hardness tester. For electrolytically-polished tungsten single crystal, sudden penetration occurred during indentation. This behavior does not occur for mechanically-polished surface. The relationship between the load and penetration coincides well with that calculated by elastic FEM analysis before the sudden penetration for electrolytically-polished tungsten single crystal. Therefore, electrolytically-polished tungsten single crystal is probably worth using as a standard material for an AFM ultra-micro hardness test.