Comments on: MMC Finds More Motor Sport Applications

By: MMC Piston Alloys « RET-Monitor

MMC Piston Alloys « RET-Monitor — Sat, 19 Dec 2009 12:12:12 +0000

[...] a previous article on the subject of advanced metals, we reported on the properties and uses of aluminium metal matrix [...]

By: Les Loushin

Les Loushin — Tue, 14 Jul 2009 20:19:59 +0000

Mr. D. M. Macdonald gives a reply on May 17th which discusses the use of fiber reinforcement from carbon or ceramic fiber materials. I did some metallurgical work in the 1980’s on metal reinforced-metal matrix composites in thixotropic cast materials. This work was done to promote the use of such materials by one of the Big Three Automakers. This work was not a large technical nor econoical successful in the 1980’s. I do not know the status of work by others since I left to do other things. The main problem was in the uniformity of thixotropic cast MMC materials.

By: d m macdonald

d m macdonald — Sun, 17 May 2009 12:55:32 +0000

You are actually referring to particulate or ceramic reinforced metals. Metal matrix compaoites are materials where the main load is taken by fibre reinforcement materials (such as carbon in the case of magensium matrices or SiCaBo [silicon carbide boron] where the matrix is aluminium. Extremely high strength to weight is possible; carbon magnesium with a carbon fibre volume of 75% is an obvious example. Where con rods and pistons are made from MMC as opposed to reinfoced metals, a fundamental redesign is needed: mmc’s have very high tensile strength whereas a ceramic material will have exceptional compressive strength. Since MMC’s allow you to tailor cte’s, a piston/rod liner assembly without the use of rings is entirely possible, able to run at high temperatures.