**5. Conclusion**

*Aluminium Alloys and Composites*

today's environment.

*3.3.4 Sports and recreation*

year [42].

to homes and businesses. Their ease of recyclability makes them a perfect fit for

In 2010, electrical market applications rose by 13.1%, and shipments of aluminium conductor steel-reinforced (ACSR) cable, bare cable, insulated wire and cable products soared to 631 million pounds, an increase of 11 million pounds from the previous year. The North American electrical market was the fourth largest for aluminium worldwide, accounting for 7.3% of all aluminium shipments during the

The sporting goods industry is not left behind as far as utilisation of AlMMCs is concerned. Aluminium metal matrix composites are very attractive as materials for sporting goods applications. The material used generally consists of an aluminium matrix reinforced with particles of silicone carbide or boron carbide. The specific strength and modulus of these materials can offer design advantages not possible with steel or carbon/epoxy composites. In addition, they have a tremendous marketing appeal for the high-end sporting goods consumer as they are a new phenomenon [50]. Recreational products, including those used in golf, cycling, baseball, skiing and other leisure as well as competitive sporting activities, have always offered profitable opportunities for high-performance materials due to the focus on performance over cost. Although AlMMCs have been used in niche applications, more widespread opportunities are available if an improved combination of performance,

manufacturability and cost can be achieved through specific R&D activities.

market opportunities for the industry if successful [16].

the need to address the following issues:

agglomerates in AlMMCs.

ness and ductility in AlMMCs.

**4. Challenges and barriers in the development of AlMMCs**

Finally, AlMMCs have been considered for specialised applications in which the combination of properties makes them especially well suited. Examples of these applications include robotics, medical, biomedical and nuclear shielding. These applications may require specific R&D activities to be carried out and technical problems solved before substantial use can occur but may represent high-value

Several challenges must be overcome in order to intensify the engineering usage of AlMMCs. Design, research and product development efforts and business development skills are required to overcome these challenges. Surappa [4] emphasised

i.A more and thorough understanding of the science of primary processing, especially the factors affecting the microstructural integrity including

ii.Need to improve the damage tolerant properties particularly fracture tough-

iii.Need for work to be done towards the production of high-quality and low-

iv.An urgent need to develop simple, economical and portable non-destructive

cost reinforcements from industrial wastes and by-products.

kits to quantify undesirable defects in AlMMCs.

**88**

AlMMCs present a great opportunity and a host of possibilities for the materials/design engineer. There are now many possibilities for manipulation of properties/property combinations to suit specific requirements of material and component properties in order to enhance performance and reliability. New and emerging technological developments point to increased utilisation of AlMMCs in current and future industrial developments. Some of the existing barriers and challenges are being addressed through various R&D efforts to find a lasting solution.

From the foregoing review, it is evident that the future of AlMMCs in various industrial and commercial applications is very bright. Advanced technological developments in primary and secondary processing of AlMMCs will continue to give them a competitive edge over the alternative materials such as Mg, AHSS and polymer composites. The main challenges and barriers that have been identified include lack of property modelling (especially the high-temperature behaviour of AlMMCs), lack of design data and high costs of primary and secondary processes. However, there are promising signs of technological breakthroughs by various research efforts dedicated to finding solutions to these challenges. New developments in CNT and nanotechnology have, for example, offered possibilities of production of AlMMCs with enhanced properties for high-temperature applications and improved wear and corrosion resistance. Other developments such as the novel rheocasting process of semi-solid alloys [e.g. see [51]] and FGMs have also offered new possibilities of cost reduction in primary production and secondary processing of AlMMCs, respectively. New alloys of aluminium have been developed for application in such areas as crash management (crash alloy)—an area previously dominated by steel. These alloys offer new R&D opportunities for further development of AlMMCs and will redefine new roles and potential of AlMMCs in automotive applications. Various researchers are also coming up with innovative cost-reduction techniques to bring down the cost of replacing conventional ferrous materials with aluminium metal matrix composites.
