Morphological evolution of NbC particles at the interface of niobium–iron diffusion couple

Abstract

To investigate the morphological evolution of the NbC phase, a niobium-cast iron diffusion couple was designed and fabricated. The two-dimensional (2D) and three-dimensional (3D) growth morphology of NbC particles were analysed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The morphological evolution mechanism of NbC particles was also discussed. The results reveal that from the interface of the Nb wire/NbC-Fe diffusion layer to the cast iron, as the thickness of the NbC-Fe diffusion layer increases, the morphology of NbC particles changed from the nearly spherical to truncated cube, then to a perfect cube. The evolution of particle morphology is mainly attributed to the change in the C/Nb ratio and the existence of Fe atoms affecting the relative growth rates of the {111} and {100} facets on a NbC crystal.

KEYWORDS:

• NbC
• in situ reaction
• morphological evolution
• growth mechanism

Acknowledgements

This work was supported by the National Natural Science Foundation of China (grant number 51974242), the Innovation Capability Support Program of Shaanxi (grant numbers 2019TSLGY04-03 and 2019-TD019), the Science and Technology Bureau of Yulin (grant number 2018-2-51), and the International Research Center for Composite and Intelligent Manufacturing Technology (grant number 2018GHJD-17).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number 51974242]; Science and Technology Bureau of Yulin [grant number 2018-2-51]; International Research Center for Composite and Intelligent Manufacturing Technology [grant number 2018GHJD-17]; Innovation Capability Support Program of Shaanxi [grant number 2019TSLGY04-03, 2019-TD019].