Mechanical properties of Al-NbAl3 in situ composites

This work analyses hardness and tensile properties at room temperature and at 150 degrees C of the in situ type of composite Al/6, 12 and 18%vol NbAl3 intermetallic phase. Composites were made by Nb dissolution in liquid Al followed by rapid cooling to provide good reinforcement dispersion. Results showed properties depending on volume fraction of NbAl3 particles as follows: increasing amount of reinforcement leads to higher Brinell hardness, sigma(0,2) (yield strength at 0,2% deformation) and sigma(max) (tensile strength) - except for 18%vol NbAl3 - and smaller epsilon (elongation). Related to the properties of the matrix alone, composites showed significant improvement in all properties but epsilon, which decreased when compared to the matrix with no reinforcement.