Boron Carbide Ceramic Metal Matrix

Aluminium matrix reinforced with b4c particles is the focus of research due to the potential for significant improvement in mechanical and thermal properties of al as a result of the incorporation of b 4 c particles.

Boron carbide ceramic metal matrix. 52 53 above 20 at carbon a eutectic reaction with a corresponding carbon content of 28 29 at occurs at approximately 2375 c. Ford offers a metal matrix composite mmc driveshaft upgrade. In this work for preparing metal matrix composite aluminium alloy lm 25 is used as base material. Alumina and boron carbide in powder form are used as the reinforcements.

The mmc driveshaft is made of an aluminum matrix reinforced with boron carbide allowing the critical speed of the driveshaft to be raised by reducing inertia. 10 wt b 4c die cast samples were produced and tested. To prevent this degradation chemical vapor deposition is used to cover the fiber surface with about 5 μm thick layer of silicon carbide sic such fibers are. Of these boron carbide is the hardest and lightest but also the most expensive and brittle.

Boron carbide composites are today favoured for ceramic plates protecting against smaller projectiles such as used in body armour and armoured helicopters. Boron carbide and silicon carbide for instance are widely used inexpensive commercial abrasives. Boron carbide chemical formula approximately b 4 c is an extremely hard boron carbon ceramic and covalent material used in tank armor bulletproof vests engine sabotage powders as well as numerous industrial applications. Boron carbide having 220 mesh size aluminium oxide and aluminium alloy ingot are required for the preparation.

The mmc driveshaft has become a common modification for racers allowing the top speed to be increased far beyond the safe. Boron carbide can be considered a prototype of the interstitial compounds of rhombohedral boron which include b 12 c 3 b 13 n 2 b 12 c 2 al b 12 o 2 b 12 as 2 b 12 p 2 sib 3 and sib 4. The density of b 4 c is lower than other commercially available ceramic reinforcements such as sic tib 2 zrsio 4 al 2 o 3 and tic resulting in composites with higher. Being mainly used in metal matrix composites boron fibers degrade on the contact with aluminum or titanium matrices at the temperature that is necessary for processing above 500 c.

This was in fact in the early sixties the first general application of ceramic armour. Half were heat treated to the t6 condition and the others were left as cast. Metal matrix composites are either in use or prototyping for the space shuttle commercial airliners electronic substrates bicycles automobiles golf clubs and a variety of other applications. In terms of tailorability a very important advan tage in mmc applications particulate reinforce ment offers various desirable properties.

5 shows the phase diagram of the boron carbon system.