*2.2.4 Cyclic extrusion and compression (CEC)*

CEC is another type of SPD technique in which the MMNC ingot is passed through the annual die to attain a fine-grained microstructure shown in **Figure 12**. The fine-grained structure in the ingot is realized using optimal temperature and the number of reciprocating passes. A typical setup of the CEC is shown in the figure below.

AZ91D/SiCn nano-composite was fabricated with refined grain structure using CEC [72]. Fabrication using the CEC was performed by varying the operating temperature from 300 to 400 °C and up to eight passes were made. Superior hardness with refined grain structure were observed.

**23**

**Author details**

Srinivasan Murugan1

1 Dhofar University, Salalah, Oman

2 Charles Darwin University, Australia

3 National University of Singapore, Singapore

\*Address all correspondence to: smurugan@du.edu.om

provided the original work is properly cited.

key to improved mechanical performance and reliability.

\*, Quy Bau Nguyen2

*Synthesis of Magnesium Based Nano-composites DOI: http://dx.doi.org/10.5772/intechopen.84189*

Present chapter provides an insight into the magnesium nano-composites that are emerging as potential candidates in many weight-critical engineering applications ranging from aerospace, automotive to sport industries. Not only they are significantly lighter than aluminum and titanium, they can also be processed using both conventional and advanced processing methods. Stir casting is the most traditional high-volume production technique capable of generating a uniform dispersion of nano-particles in the magnesium matrix. An improvement using the ultrasonic cavitation as a mean to disperse the nano-reinforcement is already attempted with promising results. Furthermore, disintegrated melt deposition technique has proved to be the most effective one because of its capability to well disperse the nano-additives and refine the microstructure which results in excellent mechanical properties. DMD is also a scalable technique. A different approach to create magnesium based nano-composites employing the chemical reaction to form nano-intermetallics during the casting period is called as in-situ casting. A semi-solid casting technique called Rheocasting applied slurry characteristics to mix the nano-particles into the matrix. The magnesium nano-composites could also be processed using powder metallurgical methodology where the raw matrix material and reinforcements are pre-mixed in powder forms using ball milling followed by compaction and sintering. Other solid-state processing techniques such as accumulative roll bonding and friction stir processing have shown tremendous promise as well. This chapter also introduces conventional and advanced secondary processing techniques such as extrusion, rolling, equiaxed channel angular pressing, and cyclic extrusion and compression. The utilization of secondary processing techniques along with primary processing techniques can lead to enhanced microstructural properties that are

**3. Conclusion**

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

and Manoj Gupta<sup>3</sup>

**Figure 12.** *Schematic diagram of CEC setup [35].*
