Diffusion multiple study of Co-Ni-Ti system at 1073 K

Abstract

Co-Ni-Ti system is a key system for thein several industrial applications. The thermodynamic and kinetic information of this system is crucial for to optimize the alloy design and process design. However, aAlthough there are many literature works on this aspectthe system has been studied largely, there are is still discrepancies onconfusion about the stability of the ternary phase _Ti(Ni0.5Co0.5)3 phase, and only few data on the diffusion information ofin the intermediate compounds as available. In this work, high throughput diffusion multiple approach was applied to investigate the isothermal section and interdiffusion of in this system at 1073K. The stability of the ternary phase _Ti(Ni0.5Co0.5)3 at 1073K was could be verifiedconfirmed based on detailed EPMA element mapping and XRD analysis. The A scheme of the isothermal section and phase relations of the Ni-Co-Ti system at 1073K including the new findings was determinedis presented. The parabolic growth constant of intermediate phases of the binary Ni-Ti and Co-Ti systems at 1073K were also calculated and the corresponding integrated interdiffusion coefficients were calculated determined using Integrated integrated Wagner Equationsequations. The obtained information are quite important for the completion of the thermodynamic and kinetic information of this key system.

Study of the FCC+L12 two-phase region in complex concentrated alloys based on the Al–Co–Cr–Fe–Ni–Ti system

“…Finally, it should be mentioned that the extent of this ternary phase may be quite large in the quaternary system as a two-phase FCC+τ domain has been experimentally confirmed for the Co52.5Ni35Ti12.5 composition ([Fe] = 0 at.%, Fig. S6) between 800°C and 1100°C [64,66,67]. Calphad predictions suggest two phases for the considered alloy composition: FCC and Ni3Ti.…”

“…The presence of the (Ni0.5Co0.5)3Ti (τ) ternary phase of hexagonal structure with the Co3V prototype is commonly observed in Co-Ni-Ti alloying systems and has been first identified by Van Loo and Bastin in the ternary system at 900°C using diffusion couple technique [62]. It has been evidenced as a stable phase between 800°C and 1100°C in recent studies [63][64][65][66][67]. The ternary phase is present in a narrow compositional region of the Co-Ni-Ti system between Ni3Ti (D024) and Co3Ti sequence and coordination geometry [65].…”

Archives of Metallurgy and Materials

“…in D sublayer, ni content is higher than Co, which increase the tendency to form γ'-ni 3 al phase. in addition, Co and ni do not form binary phases [9], so the γ' of γ + γ' sublayer is consist of more ni 3 al but less Co 3 al. Similarly, the addition of ni has the same effect to Co40al, where ni and al react in solution to form γ'-ni 3 al.…”

“…omori et al [7] studied the partitioning behavior of alloying elements in Co-al-W-based quaternary systems and showed that Ta, nb, Ti, V, Mo and W elements are partitioned into γ' phase rather than γ phase, which can improve the thermal stability of γ' phase [8]. Yuan et al [2,9] reported interfacial diffusion of Co-ni-Ti and Co-ni-Fe systems under 1173 K, and calculated the diffusion coefficients at this temperature. However, there are few reports on elements variations in W-free Co-al-X diffusion interface.…”

Diffusion multiple study of the Co-Fe-Ni system at 800 °C

“…A diffusion multiple of Co-Fe-Ni-Ti were constructed in this work. The work results of Ti-Ni-Co system on this diffusion multiple were published as another work [27].…”