Effect of in situ TiB2 particle reinforcement on the creep resistance of hypoeutectic Al-12Si alloy

The effect of in situ TiB2 particle reinforcement on the tensile creep deformation of an Al-12Si alloy prepared by the technique of salt-metal reactions was studied in a wide temperature range of 573-673 K under a constant stress in air. At the investigated temperature and stress condition, TiB2 particles significantly increase creep deformation resistance. High values of the apparent stress exponent (similar to12) and the apparent activation energy (265 kJ/mol) are observed for creep behavior of the present TiB2 particle containing Al-12Si alloy. The steady state creep rate data are rationalized by using a substructure invariant model together with the existence of a threshold stress. The excellent fit of the data of the substructure invariant model suggests that the creep deformation of the TiB2 particle containing alloy is controlled by the lattice diffusion in the aluminum alloy matrix while maintaining a constant substructure. (C) 2004 Elsevier B.V. All rights reserved.