THIXOTROPIC PROCESSING OF A6061: A STUDY ON MICROSTRUCTURE REFINEMENT AND HARDNESS IMPROVEMENT

Aluminum alloy A6061, known for its excellent strength-to-weight ratio, corrosion resistance, and extrudability, is widely used in structural and transportation applications.This study investigates the influence of semi-solid extrusion temperatures on the microstructural and mechanical behavior of A6061 alloy.Bar stock of A6061 was machined into desired geometries and subjected to semi-solid extrusion at three processing temperatures: 630 C, 635 C, and 640 C, which fall within the alloy's solid-liquid coexistence range, helping in facilitating thixotropic flow and grain refinement during extrusion.After extrusion, the cast samples were examined using optical microscopy, Vickers hardness testing, and X-ray diffraction (XRD) analysis.The observations showed that higher extrusion temperatures promoted the formation of a more uniform, globular microstructure, thereby improving hardness and overall phase stability.The XRD results verified the presence of the primary alloying phases and also indicated partial dissolution of certain precipitates as a result of the semi-solid processing conditions.The findings suggest that carefully controlled semi-solid processing can significantly improve the structural integrity of A6061 alloy, making it a promising approach for manufacturing high-performance components with refined microstructures and enhanced resistance to impact loading.