Aluminum compositesi and Fe2B

[seramist]

Hi friends,
I want to study aluminum composites and I'm interested in Fe2B particulates within the aluminum matrix. Fe2B is
a hard boride phase and used for hardnening of the steel surface. Besides Fe2B powders are very cheap and easy to find. But there is no study in literature. Is it harmfull for the properties of the aluminum composites? May the Fe2B powders find an application in aluminum sintered composites? or not? I m waiting for your comments, please.

 

[RPstress]

Iron boride is quite dense (7 g/cc) and will therefore make quite a heavy composite. Other hard, stiff particles are used with an aluminum matrix such as silicon carbide, alumina, etc. There is some info on particulate metal matrix composites at

http://www.mc21inc.com/products.html

. They seem to get anything up to a doubling of stiffness compared with ordinary Al alloy. I would expect similar results from iron boride, but because of its high density it will not be very useful. A 45% Fe₂B in Al would have a density of about 4700 kg/m³. I would expect the usual small increase in strength and a decrease in toughness compared with Al alloy. The Al matrix composite will be have less useful properties than a titanium alloy with the same density. I would be surprised if the composite was any cheaper than titanium in spite of the relatively cheapness of the boride.

Particles would usually be measured in micrometres; you might get more interesting results for nanoparticles or interesting shapes, if available.

 

[RPstress]

I've been looking up particulate reinforced material and remembered this post.

Fe2B seems to have a modulus of 355 GPa (see

http://www-brs.ub.ruhr-uni-bochum.de/netahtml/HSS/Diss/BialonArthur/diss.pdf).

This is not far off Al₂O₃ which is probably about 380 GPa and silicon carbide which seems to vary between 220 and 420 GPa.

https://www.jim.or.jp/journal/e/pdf3/43/11/2838.pdf

has SiC reinforced Al alloy.

Page 19 of "Metal Matrix Composites in Industry: An Introduction and a Survey, Volume 1" has some data on Al₂O₃ particulate reinforced Al:

http://books.google.co.uk/books?hl=..."metal matrix composites in industry"&f=false

NASA TM 107276 "Micromechanics for Particulate Reinforced Composites" has passably accurate micromechanics formulas in it (the predictions match the measured data given in the above quite well).