| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1608709 | Journal of Alloys and Compounds | 2015 | 4 Pages |
•Relationship between microstructure and permeability is theoretically analyzed.•Type and volume fraction of primary phase can be controlled by alloy composition.•Permeability of Nb–TiCo with primary (Nb, Ti) phase does not obey the mixing rule.•Permeability of Nb–TiCo with primary TiCo phase is higher than that of expected one.
The relationship between the microstructure and hydrogen permeability of as-cast Nb–TiCo alloys was investigated and is discussed on the basis of the mixing rule. The chemical compositions of these Nb–TiCo alloys may be expressed as (Nb4Ti47Co49)1−x(Nb90Ti8Co2)x. The alloys for which x = 0 and 1 exhibit essentially single TiCo and (Nb, Ti) phases, respectively. The microstructure of the alloy for which x = 0.3 is fully eutectic, and is composed of (Nb, Ti) and TiCo phases in the as-cast state. In the range of 0.3 < x < 1, the Nb–TiCo alloys present a primary (Nb, Ti) phase surrounded by a TiCo + (Nb, Ti) eutectic structure, and their hydrogen permeability values do not obey the mixing rule. In the region of 0 < x < 0.3, the alloys have a primary TiCo phase, and the hydrogen permeability values of these alloys are slightly higher than the values estimated using the mixing rule.
