Spherical nanoindentation stress–strain curves

Abstract

Although indentation experiments have long been used to measure the hardness and Young's modulus, the utility of this technique in analyzing the complete elasticplastic response of materials under contact loading has only been realized in the past few years-mostly due to recent advances in testing equipment and analysis protocols. This paper provides a timely review of the recent progress made in this respect in extracting meaningful indentation stress-strain curves from the raw datasets measured in instrumented spherical nanoindentation experiments. These indentation stress-strain curves have produced highly reliable estimates of the indentation modulus and the indentation yield strength in the sample, as well as certain aspects of their post-yield

Mechanical Characterization of Mesoscale Interfaces Using Indentation Techniques

“…41,[51][52][53] Most importantly, it has been demonstrated that the use of spherical indenters has the potential to produce indentation stressstrain curves (not just values of modulus and hardness). Furthermore, because the spherical indenters produce significantly lower concentrations in the imposed stress and/or strain fields compared to the sharp indenters, it is possible to control the indentation depths to relatively small values and investigate the local material response at low levels of plastic deformation.…”

“…40,41 Modern indenters with their impressive load and displacement resolutions and continuous stiffness measurement (CSM) capabilities have now made it possible to study systematically the mechanical responses of regions near mesoscale interfaces as a function of the distance from the interface. While the experiment itself is relatively simple (and capable of high throughput), the central challenges lie in the sample preparation 42 and in the post-test data analysis protocols employed to recover meaningful properties intrinsic to the material volume probed in the experiment.…”

Facile measurement of single-crystal elastic constants from polycrystalline samples

“…14,15 Nanoidentation modulus measurement coupled with orientation measurement using electron backscatter diffraction (EBSD) have recently been applied to obtain orientation-dependent Young's modulus, but the method has yet demonstrated the capability of evaluating the full elastic constant values. 16 Atomic force microscopy (AFM)-based methods have extremely high spatial resolutions and can quickly produce qualitative modulus maps, 17,18 but extraction of accurate elastic constants from the AFM modulus maps is still far from a reality, especially for hard materials such as metals, inorganic semiconductors, and ceramics.…”

Влияние Малоамплитудных Осцилляций Нагрузки На Наноконтактные Характеристики Материалов В Процессе Наноиндентирования

“…[11], он заключается в наложении на исходную нормальную нагрузку малоамплитудного гармонического возмущения P(t) = P a sin ωt, где P a -амплитуда добавочной гармонической силы, ω -ее частота. Благодаря наложению малоамплитудных осцил-ляций метод CSM (в отличие от OPM) позволяет непре-рывно регистрировать механические свойства исследуе-мых материалов по мере погружения индентора любой геометрии, а также определять упругие и демпфирую-щие характеристики зоны деформации образца в процес-се нагружения, а не после разгрузки индентора [12][13][14][15].…”