Impression creep behaviour of ultrasonically processed in-situ Al_3Ti reinforced aluminium composite

摘要

The creep analysis of Al3Ti reinforced Aluminium composites with different weight percent of Al3Ti particles was carried out under stresses between 113 and 170 MPa and temperatures ranging from 543 to 603 K. The microstructure showed uniformly distributed micron scale Al3Ti particles throughout the matrix due to ultrasonic stirring. The presence of Al3Ti particles refined the microstructure of the composites as it promoted heterogeneous nucleation. The results obtained from creep analysis revealed that the composites had higher activation energy and stress exponent compared to the base alloy. The improved creep behaviour is attributed to the presence of homogeneously distributed Al3Ti particles in the aluminium matrix. The obtained stress exponent and activation energy values suggest that the main creep mechanism in the base Al alloy and Al3Ti reinforced composites was lattice diffusion-controlled dislocation climb.