Limits...
Phase relations in the Nb-Ni-Cr system at 1,100 °C.

Kodentsov AA, van Loo FJ - Monatsh. Chem. (2012)

Bottom Line: It was found that nearly 28 at.% of Cr can be dissolved in the μ phase (Nb7Ni6) at this temperature, and the solubility of chromium in NbNi3 is approximately 5 at.%.The presence of this pseudo-ternary compound which is in equilibrium with all binary intermetallics and body-centred cubic (BCC) Nb- and Cr-based solid solutions largely determines the topology of the isotherm at 1,100 °C.The formation of this phase was also observed in the reaction zone between Nb and Ni-Cr solid solution when chromium concentration exceeded 15 at.%.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Materials and Interface Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.

ABSTRACT

Abstract: The isothermal cross section through the ternary phase diagram Nb-Ni-Cr at 1,100 °C was constructed by means of diffusion couples and equilibrated alloys. It was found that nearly 28 at.% of Cr can be dissolved in the μ phase (Nb7Ni6) at this temperature, and the solubility of chromium in NbNi3 is approximately 5 at.%. Under these circumstances the low-temperature (cubic) modification of the NbCr2 Laves phase can dissolve up to 6 at.% of nickel, but further increase of the Ni content (up to approximately 10 at.%) stabilizes the hexagonal (high-temperature) modification of the Laves phase. The presence of this pseudo-ternary compound which is in equilibrium with all binary intermetallics and body-centred cubic (BCC) Nb- and Cr-based solid solutions largely determines the topology of the isotherm at 1,100 °C. The formation of this phase was also observed in the reaction zone between Nb and Ni-Cr solid solution when chromium concentration exceeded 15 at.%.

No MeSH data available.


Related in: MedlinePlus

Back-scattered electron image (BEI) showing the morphology of the diffusion zone developed between chromium and two-phase alloy with the nominal composition Ni60Nb40 after annealing in vacuum at 1,100 °C for 196 h. Note that the NbNi3 domains within the microstructure of the two-phase end-member exhibit a white contrast
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4494769&req=5

Fig1: Back-scattered electron image (BEI) showing the morphology of the diffusion zone developed between chromium and two-phase alloy with the nominal composition Ni60Nb40 after annealing in vacuum at 1,100 °C for 196 h. Note that the NbNi3 domains within the microstructure of the two-phase end-member exhibit a white contrast

Mentions: The microstructure of the reaction zone developed after annealing (1,100 °C, 196 h) in the diffusion couple based on pure Cr and two-phase alloy with nominal composition Ni60Nb40 consisting of (after the equilibration) μ-Nb7Ni6 intermetallic and NbNi3 is given in Fig. 1. From the micrograph one can notice that a continuous layer of pseudo-ternary phase (henceforth designated as “T”) is a dominant reaction product in this diffusion couple. The product ternary compound appears to be in equilibrium with Cr-based solid solution as well as with both constituents of the initial two-phase alloy. The latter indicates a three-phase equilibrium NbNi3 + μ-Nb7Ni6 + T in the Nb–Ni–Cr system at this temperature.Fig. 1


Phase relations in the Nb-Ni-Cr system at 1,100 °C.

Kodentsov AA, van Loo FJ - Monatsh. Chem. (2012)

Back-scattered electron image (BEI) showing the morphology of the diffusion zone developed between chromium and two-phase alloy with the nominal composition Ni60Nb40 after annealing in vacuum at 1,100 °C for 196 h. Note that the NbNi3 domains within the microstructure of the two-phase end-member exhibit a white contrast
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4494769&req=5

Fig1: Back-scattered electron image (BEI) showing the morphology of the diffusion zone developed between chromium and two-phase alloy with the nominal composition Ni60Nb40 after annealing in vacuum at 1,100 °C for 196 h. Note that the NbNi3 domains within the microstructure of the two-phase end-member exhibit a white contrast
Mentions: The microstructure of the reaction zone developed after annealing (1,100 °C, 196 h) in the diffusion couple based on pure Cr and two-phase alloy with nominal composition Ni60Nb40 consisting of (after the equilibration) μ-Nb7Ni6 intermetallic and NbNi3 is given in Fig. 1. From the micrograph one can notice that a continuous layer of pseudo-ternary phase (henceforth designated as “T”) is a dominant reaction product in this diffusion couple. The product ternary compound appears to be in equilibrium with Cr-based solid solution as well as with both constituents of the initial two-phase alloy. The latter indicates a three-phase equilibrium NbNi3 + μ-Nb7Ni6 + T in the Nb–Ni–Cr system at this temperature.Fig. 1

Bottom Line: It was found that nearly 28 at.% of Cr can be dissolved in the μ phase (Nb7Ni6) at this temperature, and the solubility of chromium in NbNi3 is approximately 5 at.%.The presence of this pseudo-ternary compound which is in equilibrium with all binary intermetallics and body-centred cubic (BCC) Nb- and Cr-based solid solutions largely determines the topology of the isotherm at 1,100 °C.The formation of this phase was also observed in the reaction zone between Nb and Ni-Cr solid solution when chromium concentration exceeded 15 at.%.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Materials and Interface Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.

ABSTRACT

Abstract: The isothermal cross section through the ternary phase diagram Nb-Ni-Cr at 1,100 °C was constructed by means of diffusion couples and equilibrated alloys. It was found that nearly 28 at.% of Cr can be dissolved in the μ phase (Nb7Ni6) at this temperature, and the solubility of chromium in NbNi3 is approximately 5 at.%. Under these circumstances the low-temperature (cubic) modification of the NbCr2 Laves phase can dissolve up to 6 at.% of nickel, but further increase of the Ni content (up to approximately 10 at.%) stabilizes the hexagonal (high-temperature) modification of the Laves phase. The presence of this pseudo-ternary compound which is in equilibrium with all binary intermetallics and body-centred cubic (BCC) Nb- and Cr-based solid solutions largely determines the topology of the isotherm at 1,100 °C. The formation of this phase was also observed in the reaction zone between Nb and Ni-Cr solid solution when chromium concentration exceeded 15 at.%.

No MeSH data available.


Related in: MedlinePlus