Microstructural evolution and bonding mechanisms of the brazed Ti/ZrO₂joint using an Ag_68.8Cu_26.7Ti_4.5interlayer at 900 °C

Abstract

In this study, 3 mol% Y 2 O 3 -stabilized zirconia (3Y-ZrO 2 ) and commercially pure titanium (cp-Ti) joints were fabricated with an Ag 68.8 O layers were formed at the interlayer/ZrO 2 interface, while Cu 2 O was precipitated in the residual interlayer with 111 ½ Cu 2 O == 111 ½ Ag and 20 2 ð Þ Cu 2 O == 20 2 ð Þ Ag . After brazing at 900°C/6 h, a two-phase (a-Ti 1 Ti 2 Cu) region was observed on the Ti side with 2 1 10 ½ aÀTi == 100 ½ Ti 2 Cu and 0002 ð Þ aÀTi == 0 13 ð Þ Ti 2 Cu , while the TiCu layer grew at the expense of Ti 3 Cu 4 and TiCu 4 . The bonding mechanisms and diffusion paths were explored with the aid of Ag-Cu-Ti and Ti-Cu-O ternary phase diagrams.

Insight into the wetting behavior of AgCu‐xTi on ZrO2: Spreading and microstructural evolution

“…Here the AgCu‐3Ti/ZrO 2 system (900°C) is taken as a typical one to reveal the interfacial behavior. The mechanically folded AgCu‐3 wt%Ti (56.92Ag‐37.57Cu‐5.51Ti, at%), marked as M, completely melts at the testing temperature (900°C), then the melt separates into two immiscible liquids, as recommended in References 22,26,27 . It should be noted that the miscibility gap exists in the temperature range from ∼850°C (even ∼838°C) to ∼1100°C.…”

“…The mechanically folded AgCu-3 wt%Ti (56.92Ag-37.57Cu-5.51Ti, at%), marked as M, completely melts at the testing temperature (900 • C), then the melt separates into two immiscible liquids, as recommended in References. 22,26,27 It should be noted that the miscibility gap exists in the temperature range from ∼850 • C (even ∼838 • C) to ∼1100 • C. As shown in the liquidus projection of ternary Ag-Cu-Ti phase diagram (Figure 9), the position of original AgCu-3 wt%Ti (M) is very close to the tie-line at 900 • C. Approximately, the compositions of the two immiscible liquids L1 and L2 can be deduced by the red dot line passing through M F I G U R E 9 Liquidus projection of ternary Ag-Cu-Ti phase diagram 30 paralleling to the tie-line of 900 • C. According to the Lever Rule, immiscible liquids, L1 and L2 with a proportion of 90% and 10% separate from the AgCu-3 wt%Ti melt, and their compositions are 62Ag-35Cu-3Ti (at%) and 6Ag-62Cu-32Ti (at%), respectively. L1 has a proximal composition to the eutectic Ag-Cu with a low Ti content, whereas L2 is rich in Cu-Ti with a ratio of 2:1 approximately.…”

Interface evaluation on the brazed system of AlN‐Ticusil‐Graphite

“…However, the reaction phases formed in the column‐crystal–like structure might be complex. One of the possible phases of the titanium compounds was proposed by Dezellus as the reaction phase of the Ticusil braze, which follows the sequence α‐Ti, Ti 2 Cu, TiCu, Ti 3 Cu 4 , and TiCu 4 when braze was used to join with titanium . The copper within Ticusil diffused to the interface and reacted with titanium to form these reaction phases in sequence.…”

“…TiN particles were detected at the end of these column crystals. These TiN particles were speculated to have precipitated after the eutectic liquid was consumed, since nitrogen easily dissolved into the eutectic liquids TiCu and Ti 2 Cu …”

Study on the interfacial properties of active Ti element/ZrO2 by using first principle calculation

“…Many researches have been conducted to study the reaction products at the interface of AgCuTi and ZrO 2 . Wei brazed ZrO 2 using AgCuTi fillers at 900°C, and Ti 3 Cu 3 O and Ti 2 O layers were found at the interlayer/ZrO 2 interface. Dai brazed ZrO 2 and TC4 alloys using AgCu filler metals at 830‐910°C, the results also confirm the interlayers of Cu 3 Ti 3 O and TiO adjacent to ZrO 2 ceramic.…”