摘要
阐述了指数曲线拟合方法和多项式拟合方法.分别用上述方法对52条卸载过程载荷-位移曲线进行了拟合,其中多项式的最高次数分别选为2～6种.在NANOINDENTERⅡ上对13个试样进行了压入实验,试样包括4个块体材料试样和9个膜/基材料试样,最大压入深度分为2组,即:一组为200 nm和500 nm,另一组为1 μm和2 μm.在每种压入深度下,对每个试样进行两次压入.通过上述实验,13个试样可得到52条卸载过程载荷-位移曲线的数据文件.用所述拟合方法对所有卸载曲线进行了拟合并得到相应的拟合曲线参数.用所得到的参数对试样的硬度和弹性模量进行了评定,对各种曲线拟合方法得到的载荷-位移拟合曲线与实测的载荷-位移曲线之间的关系进行了分析.分析结果表明:在上述曲线拟合方法中,5次多项式曲线拟合是最佳的拟合方法,而指数曲线拟合是最差的拟合方法,曲线拟合方法对纳米压入法材料力学性能的测量结果产生较大的影响.
The fitting methods of the exponential and polynomial curves are introduced in detail. 13 samples were indented on NANOINDENTER II, including 4 bulk and 9 film/substrate samples. The maximum indentation depths were set to two groups. The depths of one group were 200 nm and 500 nm respectively, while the depths of the other group were I pm and 2 pin respectively. 4 indentations were done on each sample under the presetting indentation depth group. 52 unloading load-displacement curve data files for 13 samples were obtained. All unloading curves were fitted using different curve fitting methods and their corresponding parameters were obtained. The hardness and elastic modulus values of all samples were evaluated using the parameters, and the relations between the unloading curves and the fitting curves were analyzed. The analysis results showed that 5(th) power polynomial curve fitting method is the best one among the 6 curve fitting methods, while the exponential curve fitting method is the worst. Since curve fitting methods may have much influence on the measuring results of the material mechanical properties using nanoindentation, so much attention should be paid to the precision analysis, the standardization of the measurement and evaluation of MEMS material's mechanical properties using nanoindentation.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2005年第3期397-400,共4页
Rare Metal Materials and Engineering
基金
国家重点基础研究发展规划项目(973)(No. G1999033103)
关键词
纳米压入
曲线拟合
力学性能
MEMS
curve fitting methods
nanoindentation
mechanical properties of materials
