Carbon Fibre Reinforced Polymer (CFRP)CFRP is a composite material that is made up of a polymer matrix, usually epoxy or vinyl ester reinforced by carbon fibre. There are a few sources of carbon fibre, but usually, carbon fibre is produced from polyacrylonitrile (PAN) precursor filaments. Acrylonitrile monomer is polymerized to form PAN resin then spun and stretched into acrylic fibres. The fibres are then oxidized and carbonized. Carbon fibre has a wide range of strength and stiffness and is categorized based on its elastic modulus; low to ultra-high. CFRP is insusceptible to corrosion as it has high chemical inertness. CFRP is heavily considered to replace steel as it is about two-thirds lighter than steel, but a lot stronger and stiffer than steel (Deaton, 2015). By using CFRP to construct a car body instead of steel, up to 60% weight reduction can be achieved. A car body that is made fully from CFRP is possible as the strength and stiffness of carbon fibre can be varied when it is manufactured. Ultra-high tensile strength carbon fibre should be used for doors and sills for high energy absorption while high modulus carbon fibre should be used at the lower and upper body as these parts need to be rigid (Ferrari.com, 2013). Besides the car body, CFRP can be used in fabricating other parts of a car. Even though CFRP possesses properties that make it an excellent material for manufacture of vehicle body, carbon fibre is very expensive. CFRP costs about 20 times more than steel per kg. Also, CFRP lacks flexibility (Nicole, 2015). Metallic car body parts can be heated and repaired if there is a slight bent or crack but CFRP parts will crack and break if the force of impact is very large (Wright, 2015). The damaged part will have to be replaced. As different car parts require carbon fibre of different strength and stiffness, fabrication of the parts is labour intensive (von Koenigsegg, 2013). Therefore, a car body made fully of CFRP is not feasible.

Table 1: Physical properties of CFRPDensity, (kgm-3)Elastic Modulus (GPa)Elongation (%)Tensile Strength (MPa)

180015900-840000.5-1.91720-3690

Titanium and Its AlloysThe usage of titanium and its alloys in the automotive industry started in early 1980s (Yamashita et al., 2002) when it was used as some engine parts for race cars. Since then, the application of titanium and its alloys in vehicles have increased. The types of titanium alloy that are used most are Ti-6Al-4V and Ti-LCB (low cost beta). Due to their lighter weight and higher strength compared to steel, they are an excellent replacement for steel parts in the engine (Yamashita et al., 2002). Titanium and its alloys have lower modulus compared to steel (Azom.com, 2012), and cost about 10 times more than steel. Therefore they are not suited to be used in car body parts. Titanium and its alloys also display high resistance to corrosion so no surface treatment is needed. Due to the high strength and low modulus of this material, it is used in many parts of the car especially for springs (Sherman, Sommer and Froes, 1997). Applications of titanium and its alloys in car moving parts include valve springs, exhaust system, drive shaft, wheels and steering gear(Azom.com, 2012). The weight of a vehicle can be decreased by using titanium and its alloys in moving parts of the vehicle.

Azom.com, (2012).Titanium Alloys for Automotive Applications. [online] Available at: http://www.azom.com/article.aspx?ArticleID=1753 [Accessed 15 Apr. 2015].Build-on-Prince.com, (2013).Learn About the Best Carbon Fiber used for FRP Reinforcement and Strengthening. [online] Available at: http://www.build-on-prince.com/carbon-fiber.html#sthash.Xt6QbdLG.dpbs [Accessed 15 Apr. 2015].Deaton, J. (2015).What Is Carbon Fiber? - HowStuffWorks. [online] HowStuffWorks. Available at: http://auto.howstuffworks.com/fuel-efficiency/fuel-economy/carbon-fiber-oil-crisis1.htm [Accessed 11 Apr. 2015].Ferrari.com, (2015).LaFerrari - focus on the chassis. [online] Available at: http://www.youtube.com/watch?v=LWvMIJkip7E [Accessed 15 Apr. 2015].Nicole, W. (2015).BMWs Big Bet on Carbon Fiber. [online] Rmi.org. Available at: http://www.rmi.org/winter_2014_esj_bmws_big_bet_on_carbon_fiber [Accessed 15 Apr. 2015].von Koenigsegg, C. (2013).Carbon Fiber Construction - /Inside Koenigsegg. [online] YouTube. Available at: http://www.youtube.com/watch?v=504I_hJDFck [Accessed 15 Apr. 2015].Wright, R. (2015).Carmakers seek to use carbon fibre in mass-market vehicles - FT.com. [online] Financial Times. Available at: http://www.ft.com/intl/cms/s/0/6061140e-a806-11e4-97a6-00144feab7de.html#axzz3XO6pUv1P [Accessed 15 Apr. 2015].Yamashita, Y., Takayama, I., Fuji, H. and Yamazaki, T. (2002). Applications and Features of Titanium for Automotive Industry.Nippon Steel Technical Report, 85, p.4.