Ceramics and Composite Materials

Commercial aluminium alloys are very versatile and second only to steels in use as structural engineering material. Meanwhile, heat treatment and alloying have been recognized as the major re-engineering procedures to obtain any desired specification. In this study, a clear case of the effect of post-production processing and its consequent microstructure and effectual changes in mechanical properties of a commercial Aluminum 6063 alloy is presented. The control sample is a normalized as-received aluminum alloy from Overseas Aluminum, India. It has been observed that at constant elemental composition; when this control sample was annealed at 260°C for 2 hours below its lower critical extrusion temperature of 413°C (775°F) and followed by regulated cooling at 10°C (50°F) per hour in a Muffler furnace, there was morphological

and property evolution. The samples were analyzed using Optical and Scanning Electron Microscopy with inbuilt EDX. The observed change in morphology prompted further analysis using XRD to confirm possible phase transition in the alloy at constant elemental composition as a result of noted change in grain refinement, more ductility and toughness in the annealed sample. From the results obtained, it can be said that mechanical properties depends largely upon the various form of heat treatment operations and cooling rate. Hence depending upon the properties and the applications that may be required for any design purpose, a suitable form of heat treatment normalizing, annealing or quenching should be adopted. For high ductile and minimum toughness, annealed aluminium 6063 will give satisfactory results.