Good mourning, people are aquinted to extract mechanical properties from micro-indentation values, here we talk about the Yield strength and Ultimate tensile strength, and mainly this works well for homogeneous materials and mostly in metals, so is it possible to do so for non-homogeneous materials, and if is it so could anyone give us some documents and references about that, THANKS
For non-homogeneous materials (and basically, the grain structure of metallic materials makes almost every alloy inhomogeneous) you would need to test each grain or at least each constituent independently. For typical alloys, it requires nano-indentation to hit individual grains. From the data acquired in such an experiment, it is possible to determine the single crystal behavior.
See http://zambaldi.de/pub/ for some publications related to that approach.
Thanks Mr Martin Diehl for your valuable answer and the link that you have given it is very helpfull, i have a little question, let's suppose that i have a non-homogeneous material with two constituants and that the structure is random, is it appropriate to compute an averaged value of the extracted mechanical properties (obtained using the nano-indentation technique) avereged over the values obtained for (let say) each phase of the considered constituant in a too smal area? is this an appropriate manner and is there any restrictions over the size of the area concidered? thanks again
Nice to hear that you like the link
The answer to your question will definitely depend on many parameters, but in general one cannot compute the mechanical answer of a multi constituent material by plain averaging. Think of a pudding with 50% hazelnuts: Its stress--strain response will be definitely dominated by the pudding's behavior. In contrary, for moderate mechanical contrast between the constituents (i.e. in polycrystals), the effect is not that pronounced and might be negligible.
Thanks Mr Martin Diehl for your answer, one have to continue digging since this matter according to your answer involve several parameters that are not fully understood so far mainly because of the verstality in the domain of non-homogeneous materials. there is some of aspects that came out from your answer and i must make readings about for one who want to put himself effeciently into the matter. Otherwise i thank you a lot and i'll keep asking if you don't mind :).
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