Abstract
Micro-indentation testing is particularly well-suited for evaluating the mechanical properties of small areas and thin films, offering the advantage of assessing characteristics at very shallow depths on the micro -scale. Various methods have been proposed for estimating stress-strain curves based on micro-indentation tests. However, traditional approaches typically rely on averaged results from multiple tests, which leads to insufficient consideration of the scatter observed in these results. Scatter is commonly observed in the outcomes of micro-indentation tests, arising not only from the testing apparatus but also from the microstructural characteristics of the specimens, a phenomenon that is unique to micro -scale testing. Identifying the factors contributing to this scatter can facilitate more accurate estimations. In this study, the influence of grain boundaries on the scatter of nano-indentation test results was investigated. The distance from the grain boundary to the center of the indentation was plotted against both the indentation modulus and hardness. The results of plotting the indentation modulus and hardness against the distance from the grain boundary to the center of the indent showed a slight increasing trend as the proximity to the grain boundary increased; however, no significant differences were observed. Notably, hardness was found to be more significantly affected by the grain boundary compared to the indentation modulus. Furthermore, a comparison of the average values of data near the grain boundary and within the grains revealed a difference of less than 1%, indicating th at no substantial inhomogeneity was present.
