Rapid growth kinetics of β-Fe3Ge2 intermetallic compound within undercooled liquid Fe–Ge alloys
Abstract
The rapid dendrite growth of the β-Fe3Ge2 intermetallic compound within two liquid Fe–Ge alloys was investigated using the bulk undercooling technique. The liquid undercooling was achieved up to 202 K (0.14TL) and 227 K (0.16TL) for hypereutectic Fe70Ge30 and Fe67Ge33 alloys, respectively, where the primary β-Fe3Ge2 phase always exhibited non-faceted growth characteristics. Within the Fe70Ge30 alloy, the β-Fe3Ge2 phase morphology transformed from columnar to equiaxed dendrites with increasing undercooling, where the maximum growth velocity was measured as 1.44 m/s at 141 K undercooling. Beyond this undercooling threshold, the (β-Fe3Ge2 + α1-Fe17Ge3) anomalous eutectic grew directly from the undercooled liquid, which may be attributed to the remarkably enhanced nucleation rate of the α1-Fe17Ge3 phase. For the Fe67Ge33 alloy, the primary β-Fe3Ge2 dendrites achieved a high growth velocity of 3.53 m/s at the maximum 227 K undercooling. Furthermore, the Vickers hardness of the β-Fe3Ge2 compound in these two alloys was improved significantly, which resulted mainly from microstructure refinement.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (4)
N. S. Hou
MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University , Xi'an 710072,
D. L. Geng
MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University , Xi'an 710072,
G. Y. Zhu
MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University , Xi'an 710072,
B. Wei
School of Physical Science and Technology, Northwestern Polytechnical University 1 , Xi’an 710072,