Evaluation of discontinuities in friction stir welds of aluminum matrix composites

The purpose of this paper is to evaluate the welding quality of the friction stir joints of Al-SiC with diverse shape of pin geometry tools.

Aluminum matrix composites are gaining unlimited interest and special position in aeronautical industry because of their properties enhanced by the presence of ceramic reinforcement, such as lower density, dimensional stability, exceptional wear and abrasion resistance. Friction stir welding arises as a promising welding process with more advantages than traditional fusion process in the joining of aeronautical components with the utilization of a non-consumable rotational tool shaped by a shoulder and a pin, which can be designed in as many possible geometries. However, the welding quality is not always achieved when varying these pin configurations.

The fabrication and implementation of different pin geometry tools to weld the plates of the material allows to study the behavior of the joints assessing some discontinuities produced in the welds.

To examine the microstructural evolution and its behavior in the different zones of the joint, the practical implication consists in the use of different characterization techniques like the optic microscopy and scanning microscopy, furthermore mechanical test such as the measurement of hardness.

The study of the joints uses different welding tool geometries that were fabricated at prototype scale contribute in the microstructural analysis as well as in the evaluation of the possible discontinuities that are presented.