THE HIGH-TEMPERATURE CREEP-BEHAVIOR OF AN AL-1 WT-PERCENT CU SOLID-SOLUTION ALLOY

The creep behaviour of an Al 1 wt% Cu solid-solution alloy is investigated at a temperature of 81 3 K under stress range of 0.5-5 M Pa. The creep characteristics of the alloy including the stress dependence of the steady-state creep rate (n = 4.4), the shape of creep curve (normal primary stage), the transient creep after stress increase, and the value of the true activation energy for creep, suggest that some form of dislocation climb is the rate-controlling process at higher stresses above 1 MPa. However, at low stresses ( < 1 MPa), the creep curves show no distinguished steady state, and the stress dependence of the minimum creep rate is as high as approximately 8. The creep behaviour of the alloy is discussed based on recent theories available for describing creep in solid-solution alloys.