A study of Al₂Ti precipitation in a Cu-modified Al₃Ti alloy

Abstract

An equilibrium precipitation of Al 2 Ti is shown to occur within a Cu-modified Al 3 Ti alloy having the Ll 2 structure. This precipitation is analyzed by conventional and high resolution electron microscopy and some insights are given concerning the mechanisms of nucleation and growth of Al 2 Ti within the Ll 2 matrix. In the meantime, Vickers microhardness tests have been performed as a first approach to the mechanical behavior of this alloy and the results are compared to measurements obtained in an actual single-phased Ll 2 compound. The Al 2 Ti precipitation seems to have an important hardening effect.

A Study of the Kinetics of Phase Transformations in Nb-Ti-Al Alloys

“…The I4/amd space group of the 0 phase is, however, the same as the TiAl 2 intermetallic compound [27,[60][61][62][63][64]. In the binary Ti-Al system, the TiAl 2 phase can take on two different crystal structures h-TiAl, and r-TiAl 2 depending on temperature [27] (see Figure 3.18).…”

Trialuminide intermetallic alloys for elevated temperature applications—overview

“…In contrast, Winnicka and Varin [57] suggested that hardness is rather dependent on Ti content instead of the atomic number of the macro-alloying element. However, it has recently been demonstrated that the increasing hardness in high Ti L12 trialuminides (above stoichiometric 25 at.%) is associated with a precipitation hardening arising from AIzTi precipitation [58,59].…”