Processing and Characterization of Light Metal Matrix Composites (LMMCS)

An initial bimetal magnesium/aluminium (Mg shell / Al core) macro-composite containing millimeter-scale unthreaded Al core reinforcement was fabricated via casting and hot-extrusion. This macro-composite was characterized in detail and conceptually developed through 3 stages. Initially, the Al volume fraction was not uniform in the macro-composite. In the first stage consequently (Concept 1, Chapters 4-6), threading was used to achieve a fairly uniform Al volume fraction in the macro-composite. This significantly enhanced the tensile ductility of magnesium but the tensile strength of magnesium was compromised due to inadequate Mg/Al macro-interface and increased grain size. Consequently in the second stage (Concept 2, Chapters 7 and 8), the Mg/Al macro-interface was strengthened (in tension) by systematic substitution using AZ31 shell and AA5052 core. Tensile strength was eventually significantly increased without significant drop in ductility. Consequently in the third stage (Concept 3, Chapters 9-12), Al2O3 and carbon nanotube (CNT) nanoparticles were individually integrated with the AZ31 shell to increase the tensile ductility of the macro-composite without significant drop in strength. The microstructure and mechanical properties of the individual AZ31 nano-composites were also studied. In each case, the tensile strength and ductility of AZ31 were enhanced simultaneously and significantly.A total of 13 journal papers and 4 conference papers are derived from this PhD thesis. Further, 1 journal paper and 1 conference paper are under review. Also, 2 books and 1 journal paper are in preparation. Please refer to List of Publications on page vii.

Author dc:creator

• MURALIDHARAN S/O PARAMSOTHY

• Mg-Al macrocomposite, AZ31-AA5052 macrointerface, Carbon nanotube, Nanocomposite, Texture, Mechanical properties