STEADY-STATE CREEP-BEHAVIOR OF A RAPIDLY SOLIDIFIED AND FURTHER PROCESSED AL-5 WT-PERCENT TI ALLOY

The steady state creep behaviour of a rapidly solidified and further p rocessed Al-5 wt% Ti alloy has been studied in the temperature range 5 73-673 K. The experimental data exhibited apparent stress exponents of 7-8 and an apparent activation energy of 240 kJ mol-1. The results ar e analyzed using the semi-empirical power law, the substructure invari ant 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 re presentation for steady state creep of such alloys. By analyzing liter ature data on the metallic/intermetallic dispersion strengthened alumi nium alloys, a modification in the dimensionless constant, A = 8.3 x 1 0(3) exp[-104 square-root (b/L)], is suggested to account for the infl uence of dispersion on creep kinetics. It is proposed that the attract ive 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.