Mechanical and microstructural behaviour of friction stir welded Al6061/Cr2O3 metal matrix composite.

Aluminium metal matrix composite are widely used in various field like aerospace, marine and automobile application. The application of composites necessitates joining process and its difficult due to different materials. To address the considering difficulties the present study is, Cr2O3 was reinforced in Al 6061 matrix in 2% to 6% in the incremental step of 2%. The stir casting technique was used to fabricate the composites with 300rpm stirring speed and the stirring time duration was 3min throughout the fabrication process. The PCBN tool is used for prepared friction stir welded (FSW) joints and tool having 6.7mm pin diameter and 6mm pin height. The fabrication process is conducted by 1000rpm tool rotational speed and 25mm/min welding speed. The atmospheric and underwater environmental conditions was preferred to perform friction stir welding. The mechanical properties of the joint, such as tensile strength (ASTM E8), hardness (ASTM E18) and impact strength (ASTM E23) are investigated. The microstructure of welded joints is analyzed by X-ray diffraction. The sample one composite having high tensile strength, sample two having high impact strength then other samples. Microstructure reviewed that the fracture surface shows Dimple appearance.