Article ID Journal Published Year Pages File Type
1583062 Materials Science and Engineering: A 2008 7 Pages PDF
Abstract
Microstructure evolution of Ni-24.19 wt%Nb hypereutectic alloys was investigated to develop a method to increase the productivity of in situ composite in directional solidification. The results show that at the constant growth velocity of 10 μm/s, coarse priamry β-Ni3Nb plate dendrites were firstly precipitated from the liquid. However, at the growth velocity changing abruptly from 1 μm/s to 10 μm/s, only coupled growth eutectics were observed in the solidification microstructure. The coupled eutectic growth stable at 10 μm/s is possibly ascribed to the interface growth temperature of coupled eutecitc exceeding that of β-Ni3Nb single phase. Another probable factor to permit the coupled eutectic growth stable at 10 μm/s is the difficult nucleation of β-Ni3Nb phase in front of the eutectic growth interface. By changing solidification process, the productivity for the formation of in situ composite of Ni-24.19 wt%Nb hypereutectic alloy is improved by a factor of 5.
Related Topics
Physical Sciences and Engineering Materials Science Materials Science (General)
Authors
, , , , ,