Deviations in determining coatings' and other materials' mechanical properties, when considering different indenter tip geometries and calibration procedures
Deviations in determining coatings' and other materials' mechanical properties, when considering different indenter tip geometries and calibration procedures
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DOI：
10.1016/j.surfcoat.2007.07.042
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发表时间：
2007-12
影响因子：
5.4
通讯作者：
K. Bouzakis;N. Michailidis
中科院分区：
文献类型：
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作者：
K. Bouzakis;N. Michailidis
在ISO 14577-4标准中，提出了估算压头面积函数和框架遵从性的各种程序。最近，一种fem支持的方法对纳米压痕进行逐步试错模拟，可以确定材料的应力-应变规律，并且可以精确地描述等效压痕尖端的几何形状。本文提出了该方法的一种改进，允许定义精确的压头倾角和压头面积函数（TiGAF算法：尖端几何和面积函数）。采用TiGAF算法，并在ISO14577-4（方法3）之后，按照上述步骤，对涂层、硅（100）、玻璃BK7、熔融二氧化硅、钨、钢等各种材料进行纳米压痕测试，并利用相关结果确定压痕面积函数。所得结果的比较显示出很好的一致性。此外，通过采用适当的基于fem的技术，通过假设不同的压头尖端几何形状，努力接近TiAlN涂层的应力应变曲线。当压头尖端几何形状与TiGAF算法确定的形状不一致时，压头的应力-应变特性与标称应力-应变特性存在较大偏差。
In the ISO 14577-4 standard various procedures for estimating the indenter area functions and the frame compliance Cfare proposed. Recently, a FEM-supported method performing a stepwise, trial and error simulation of nanoindentation, enabled the determination of materials stress–strain laws and moreover the precise mathematical description of an equivalent indenter tip geometry. An evolution of this method is presented in this paper, allowing the definition of the exact indenter inclination angle and of the indenters’ area functions as well (TiGAF algorithm: Tip Geometry & Area Function). Various materials, including coatings, Silicon (100), glass BK7, fused silica, tungsten, steel, etc were tested by nanoindentations and the related results were used to determine the indenter area functions, according to the aforementioned procedures by the TiGAF algorithm and after ISO14577-4 (method 3). A comparison of the obtained results revealed a good agreement. Furthermore, an effort to approach the stress–strain curves of a TiAlN coating, by assuming various indenter tip geometries, was realized by employing appropriate FEM-based techniques. The application of indenter tip geometries diverging from the determined one by the TiGAF algorithm led to significant deviations of the different stress–strain characteristics from the nominal ones.