Abstract
Experimental study was carried out on high temperature mechanical behavior of L12-trialuminides, (Al, Cr)3Ti and (Al, Cu)3Ti. Focus was on the nature of the serrated flow which occurs in a relatively low temperature range at the critical strain. Serrated flow was observed during deformation in compression at temperatures as low as 473K. The critical strain for the onset of the serrated flow depends on strain rate and test temperature. Higher temperature or lower strain rate results in a smaller critical strain. A simple analysis of the data by the use of an equation based on the theory of dynamic strain aging by solute atoms gives an apparent activation energy smaller than 100kJmol-1 for both (Al, Cr)3Ti and (Al, Cu)3Ti alloys. The measured activation energy is much smaller than the reported activation energy for the diffusion of substitutional solutes in L12-trialuminides, implying that the diffusion of interstitial solutes is responsible. Possible diffusion process in ordered L12-(Al, X)3Ti alloys with low activation energy are discussed.
