Microstructural Evolution and Formation Mechanism of the Interface Between Titanium and Zirconia Annealed at 1550°C

Abstract

The diffusional reaction between titanium and zirconia was carried out isothermally at 1550°C in argon. The distinct reaction layers in the reaction‐affected zone between Ti and ZrO2 were investigated using analytical scanning electron microscopy, analytical transmission electron microscopy, and electron probe microanalyses. In the metal side, there existed five reaction layers in a sequence of α‐Ti(O), Ti2ZrO+α‐Ti(O, Zr), Ti2ZrO+α‐Ti(O, Zr)+β′‐Ti (O, Zr), α‐Ti (O, Zr)+β′‐Ti (O, Zr), and β′‐Ti (Zr, O) after cooling. In the zirconia side, two reaction layers were found: near the original interface, β′‐Ti coexisted with fine spherical c‐ZrO2−x and Chinese‐script‐like c‐ZrO2−x, which dissolved a significant amount of Y2O3 in solid solution; further away from the original interface, the coarsened intergranular α‐Zr was excluded from metastable ZrO2−x, resulting in the lenticular t‐ZrO2−x and ordered c‐ZrO2−x. An attempt was made to determine and propose the microstructural evolution and formation mechanism of the reaction layers between titanium and zirconia isothermally annealed at 1550°C.

Effects of Annealing Temperature on Microstructural Development at the Interface Between Zirconia and Titanium

“…At a higher magnification, it was seen that the amount of acicular a-Ti(Zr, O) gradually decreased toward the original interface. 13 Lin and Lin 13 indicated that the acicular a-Ti was precipitated from the b 0 -Ti matrix by means of the ledge mechanism. In contrast, the reaction layer ''III'' was not found after annealing at 11001 or 13001C.…”

“…1(d), consisting of b 0 -Ti and the lamellar Ti 2 ZrO1a-Ti. The microstructural development on annealing at 15501C and after subsequent cooling has been described previously 11,13 and schematically shown in Fig. 7(d).…”

“…Recently, Lin and colleagues [8][9][10][11][12][13] have thoroughly investigated the diffusional reactions between titanium (or titanium alloys) and zirconia. Using transmission electron microscopy (TEM)/ energy-dispersive spectrometer (EDS) analyses, they indicated that the ordered titanium suboxide (Ti 3 O) and the orthorhombic lamellae Ti 2 ZrO were formed in the solid solution of a-Ti(O) between zirconia and titanium melt during cooling from 17001C.…”

“…11 Furthermore, the acicular a-Ti(O) was precipitated in the b 0 -Ti(O, Zr) matrix with two various orientation relations in the metal side. 13 One was determined to be ½2 13 In the zirconia side, far away from the interface of Ti/ZrO 2 , Lin and Lin 12 also observed twinned t 0 -ZrO 2Àx , lenticular t-ZrO 2Àx , and/or ordered c-ZrO 2Àx as well as the intergranular a-Zr after annealing at 15501C.…”

Omega-phase in Ti-Hf-Zr alloys produced by the hydride-cycle methodSpecial issue on Neutron Scattering in Canada.

“…The presence of the ''Ti 2 ZrO'' u-oxide is well-established experimentally [13,14,[22][23][24][25][26], although its existence is not widely appreciated. Domagala et al reported a study of the pseudobinary Ti-ZrO 2 phase diagram, showed ZrO 2 to be highly soluble in Ti, and reported the existence of a distinct binary oxide [22].…”