when to use weight percentage and when to use volume fraction in composites?
The weight percentage is preferable when volume fraction is difficult for the measuring, for example, in case of hydrophobic filler (large error of volume determination by hydrostatic method) and in case of reactivity of filler to water or another fluid for hydrostatic measuring of filler volume. But volume percentage is more convenient for "realizability".
The weight percentage is preferable when volume fraction is difficult for the measuring, for example, in case of hydrophobic filler (large error of volume determination by hydrostatic method) and in case of reactivity of filler to water or another fluid for hydrostatic measuring of filler volume. But volume percentage is more convenient for "realizability".
but why they will use vol. fraction in Cu-Diamond composite
like Cu-1wt% Cr- 20 vol % diamond
there while representing diamond content why they use vol. fraction why not weight percentage
This looks liek a very specific example. Are you sure that it isn't a typographical error? It is not usual to mix units in that way.
I've gone through 20 journals ,all of them have expressed composition in same manner
refer this book
Composites Engineering Handbook
edited by P.K. Mallick
Dear David, your answer is a witty, but the reason of this "mix", cited by
Gaurav Kant, most likely connected with essentially different density and surface properies of components.
When its difficult to know the Density of the materials we go for % of weight .. if we know the density, can go for % volume..
You have a metal mixture that is likely a single phase alloy. Absent the diamond, the composition would be expressed in wt%. Adding the diamond makes this a particle composite. The properties of particle composites depend on vol% using either a simplex, inverse, or complex rule of mixtures.
As an example, the density is an inherent property that follows the simple rule of mixtures. Find the density of the Cu+Cr alloy as DCuCr using densities Dj and weight fractions wj of components j as
DCuCr = mCuCr / VCuCr = (wCu + wCr) / ((wCu/DCu) + (wCr/DCr))
(assumes volume conservation applies). The density of your particle composite would be
Dpc = fd Dd + (1 - fd) DCuCr
where fd is the volume fraction of diamond.
Further information on particle composites is found in any textbook on materials science and engineering.
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