The Al–B–Nb–Ti system

Microstructure characterization, mechanical properties and toughening mechanism of TiB 2 -containing conventional cast TiAl-based alloy

“…According to the Al-B-Ti ternary system phase diagram [34], the ternary liquid surface in the region of interest is shown in Fig. 11.…”

“…Projected view of the Ti-Al-B liquidus surface[34]. (For interpretation of the references to color in this figure, the reader is referred to the web version of this article.…”

Grain refinement of TiAl-based alloys: The role of TiB2 crystallography and growth

“…TiB 2 precipitates prior to b in the melt of, for example, Ti-45Al at.% alloys with boron contents larger than 1.5 at.% [4]. b forms via the eutectic reaction L ?…”

“…The thermodynamic description of the system Ti-Al-B [4] enables a new investigation of this grain refinement mechanism in terms of alloy composition and phase formation. It has been shown that in case of low-boron content, nucleation of the hexagonal close-packed (hcp) a phase on borides appears to be the grain refinement mechanism [5].…”

Grain refinement of TiAl alloys by isomorphic self-inoculation

“…Relatively small amounts of boron are added to the melt and titanium boride (TiB) or diboride (TiB2) precipitate as nucleants. These precipitates can nucleate α or β phases depending on alloy composition, and have been found to have orientation relationships with both phases, which indicates a good lattice mismatch between them [11], they are also thermodynamically stable in the melt [12]. However, in some cases the borides which form can have flake [13] or needle like [14] morphologies.…”