Transformations β → ω dans les alliages metalliques du systeme ternaire TiZrO

Abstract

The X-ray study of the metallic alloys in the ternary system TiZrO shows the existence of phases α, β, ω (o) and of a new phase ω′ (o). This phase ω′ (o) appears in the alloy Ti 2ZrO after a long anneal at low temperature. Its structure is described in the space groupe Cmmm ( a = 4,8387 A ̊ ; b = 8,1486 A ̊ ; c = 6,1042 A ̊ ; 8 Ti atoms in 8 n with y = 0,338 and z = 0,254; 4 Zr atoms in 2 a + 2 d; 4 0 atoms in 4 e). The filiation of the phases shows the existence of ordering phenomena in the distribution of Ti and Zr atoms during the transformation β → ω (o), and in the distribution of 0 atoms during the transformation ω (o) → ω′ (o).