Study of the influence of FSP parameters affecting the thermal properties of Al6061 composites.

Composites prepared by Friction stir processing (FSP), having exceptional surface characteristics, are being widely used in various thermal environments, such as in automobiles and aircraft industries. The addition of one or more ceramic reinforcements may improve their thermal conductivities and reduce the thermal expansion coefficients leading to greater dimensional stability thereby making them more efficient for such applications. In the present work, FSP is utilized to fabricate surface composites with varying compositions of copper and graphene powders as the reinforcements. The composites prepared are inspected for their thermal and microstructural characteristics for different reinforcement compositions and FSP pass numbers. It is observed that the composites with higher copper weight% have higher thermal expansion coefficient in comparison to that with lower copper weight%. Also, the addition of higher graphene content in the aluminium alloys lowers the coefficient of thermal expansion (CTE) of the composite and vice-versa. Besides, the composites prepared by lesser number of passes (two) have higher values of CTE than that prepared by higher number of passes (four). This is due to the reason that the microstructure of the composite is more refined when prepared with more pass numbers and so the space between the particles is lesser preventing the tendency of the sample to be easily be expanded on heating. This approach finds a wide scope to draw useful insights for the composite fabrication conditions for their high temperature applications. [ABSTRACT FROM AUTHOR]