Rapid Publication: Effect of Grain Size on High-Temperature Creep Behavior of #gamma#-Ti-53 mol percent Al Intermetallics in the Low Stress Region

摘要

Creep tests were carried out at 1100 K on a single-phase off-stoichiometric #gamma#-TiAl having two grain sizes, d=40 and 70 #mu# m, over the stress range from 63 MPa to 300 MPa. The influence of din the range from 40 #mu# m to 200 #mu# m on creep behavior was discussed. Under low stresses, region III, the creep rate once reaches its minimum, #epsilon#_m. It then increases significantly and reaches the steady-state value, #epsilon#_s. The absolute value of #epsilon#_m depends on d, but #epsilon#_s does not depend on d. With decreasing d, #epsilon#_m increases and the strain for #epsilon#_m decreases: #epsilon#_m~(III) propor.to d~(-0.6). It is suggested that at a critical grain size, about 10 #mu# m under the present creep condition, creep enters into the steady-state at a very early stage of deformation.