Mobility Database

PanNb2025_MB is an atomic mobility database for Nb-based alloys, which is compatible with the PanNb2025_TH thermodynamic database and suitable for the simulation of diffusion-controlled phenomena using the PanDiffusion module, PanEvolution module, and/or PanSolidification module.

Phases

The atomic mobility within the Liquid, Bcc, Fcc, and Hcp solution phases are assessed in this database.

Self-diffusivity of Pure Elements

The color represents the following meaning:

	:	Validated
	:	Estimated
	:	No data

**Table 1:** Assessed self-diffusivity of pure elements with different crystal structures

Assessed Systems

In addition to the assessed self-diffusivities shown above, the impurity diffusion data for all elements included in the current PanNb2025_MB mobility database are also assessed. Moreover, chemical-diffusivities available in some binary and ternary systems are also used to assess the interaction parameters. These binary and ternary systems are listed below for the Bcc, Fcc, and Hcp phases, respectively.

Fcc Phase

Al-Si

Al-W

Cr-Fe

Cr-Ni

Fe-Si

Bcc phase

Al-Fe	Al-Ti	Cr-Fe	Cr-Ti	Fe-Ti	Hf-Zr	Mo-Nb	Mo-Ta	Mo-Ti	Mo-W
Mo-Zr	Nb-Ta	Nb-Ti	Nb-V	Nb-W	Nb-Zr	Ta-Ti	Ta-W	Ti-V	Ti-Zr
V-Zr

Al-Cr-Ti

Al-Fe-Ti

Database Validation

The simulated concentration profiles of a series of Nb-based alloys are shown below to validate the current PanNb2025_MB database.

Figure 1: Inter-diffusion of Ta in bcc Nb-Ta alloys at different temperatures [2013Liu]

Figure 2: Inter-diffusion coefficients of Nb in bcc Nb-W alloys at different temperatures[2013Liu]

Figure 3: Inter-diffusion coefficients of Nb in bcc Nb-Zr alloys at different temperatures [2008Liu]

[2008Liu] Y. Liu, et al., Study of diffusion mobilities of Nb and Zr in bcc Nb-Zr alloys. Calphad, 32 (2008): p. 455-461.

[2013Liu] Y. Liu, et al., Mobilities and diffusivities for bcc Nb-W, Nb-Ta, Zr-Mo and Zr-Hf alloys. Journal of Alloys and Compounds, 2013. 555: p. 381-389.