Cu-Al固溶体合金の高温定常クリープ変形

Abstract

The high-temperature steady-state creep behavior of Cu and Cu-Al solid solutions containing 2.5 and 15 at% Al was studied in the temperature range from 450 to 700°C. The results obtained are as follows: (1) The steady-state creep rate \dotε can be represented as a power of stress σ according to \dotε∝σn, and the value of n is about 9 for pure copper and about 5 for Cu-Al solid solutions. The steady-state creep rate also can be represented as a function of the mean effective stress \barσ*, namely \dotε∝\barσ*n*, and the value of n* is about 5 for pure copper and about 3.5 for Cu-Al solid solutions. (2) The mean internal stress \barσi at steady-state creep determined by the stress dip test depends on the applied stress, concentration of solute atoms and temperature. The value of \barσi⁄σ decreases with the applied stress and temperature, and increases with the concentration of solute atoms. (3) The activation area A* is a function of the mean effective stress \barσ* and A*\barσ*=const. The activation area does not depend on the concentration of solute atoms. (4) The steady-state creep rate increases with stacking fault energy γ, following an emprical relation of the form \dotε∝γm, and m is 1.1∼1.4 for Cu-Al solid solutions.