Abstract
A kinetic model for ternary systems was developed based on the microscopic diffusion form of the phase-field equations describing the precipitation process in binary alloys. The model was used for atomic simulation of the initial precipitation mechanisms of γ′ and θ ordered phases in Ni75Al11V14 and calculation of the order parameters of γ′(Ni3Al) phase. The results show: the γ′ ordered phase precipitated from the disordered matrix by a nonclassical nucleation mechanism accompanied by spinodal decomposition, and an initially formed nonstoichiometric ordered phase later transformed into the stoichiometric one; clusters of V atoms appeared at the γ′ phase boundary resulting in the formation of a nonstoichiometric θ ordered phase; the degree of ordering of the O domain decreases with distance from the γ′-phase boundary. There exists two types of DO22 ordered domains: horizontal and vertical, depending on their adjacent γ′ phase boundary.
Original language | English |
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Pages (from-to) | 701-705 |
Number of pages | 5 |
Journal | Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering |
Volume | 33 |
Issue number | 7 |
State | Published - Jul 2004 |
Keywords
- Computer analysis
- Precipitation mechanism
- Ternary alloy
- Two ordered phases