Steady state creep behaviour of a rapidly solidified and further processed Al-5 wt% Ti alloy

Abstract

The steady state creep behaviour of rapidly solidified and further processed Al-5 wt% Ti alloy has been studied in the temperature range 573–673 K. The experiememtald ata exhibited apparent stress exponents of 7–8 and an apparent activation energy of 240 kJ mol−1. The results are analyzed using the semi-empirical power law, the substructure invariant model and an exponential law. The semi-empirical power law with a threshold stress and a stress exponent of 5 is found to be the best representation for steady state creep of such alloys. By analyzing literature data on the metallic/ intermetallic dispersion strengthened aluminium alloys, a modification in the dimensionless constant, A = 8.3 × 103 exp[−104√(b/L)], is suggested to account for the influence of dispersion on creep kinetics. It is proposed that the attractive dislocation-particle interaction originates from the dissociation of lattice dislocations into interfacial dislocations when they enter the matrix-particle interface at high temperatures for climb by-pass.