An assessment of the method used to determine activation parameters in L1{sub 2} alloys

The characterization of dislocation mechanisms in connection with macroscopic mechanical properties are usually performed through transient tests, such as strain-rate jumps, load relaxations or creep experiments. The present paper includes a careful and complete theoretical analysis of the relaxation and the creep kinetics. The authors experimentally show that the plastic strain-rate {dot {epsilon}}{sub p} is continuous at the transition between constant strain-rate conditions and both load relaxation and creep test. The product of the plastic strain-rate at the onset of the transient test ({dot {epsilon}}{sub p0}) with the characteristic time (t{sub k}) of the transient is found to be independent of {dot {epsilon}}{sub p}, as theoretically expected. This is a clear indication that the assumptions underlying the theoretical analysis are relevant. This paper is an attempt to correlate the results obtained by comparing logarithmic creep and logarithmic relaxation behavior of Ni{sub 3}Al polycrystals.