EFFECT OF SUPERIMPOSED LOW-FREQUENCY OSCILLATIONS ON THE STATIC CREEP-BEHAVIOR OF AL-1 WT-PERCENT SI AND AL-1 WT-PERCENT SI-0.1 WT-PERCENT ZR-0.1 WT-PERCENT TI ALLOYS

Torsional oscillations of increasing frequencies with constant torsion al strain amplitude, theta, of 3.1x10(-4) were superimposed on wires o f Al-1 wt% Si and Al-1 wt% Si-0.1wt% Zr-0.1 wt% Ti alloys, while being crept under constant stress (52.3 MPa) and different testing temperat ures. It was found that increasing the frequency of oscillations resul ted in an increase of both transient and steady state creep. In the tr ansient stage, while the exponent n is increasing with frequency v, th e parameter beta decreases. Zirconium and titanium addition generally reduced the rate of creep. A value of 20 kJ/mol was found for the acti vation energy of the mechanism operating in the transient and steady s tate stages which was ascribed as being due to dislocation intersectio n.