Computer simulation for precipitation process of θ (Ni3V) and γ′ (Ni3Al) with microscopic phase-field method
(1.山西省太原市北方大学材料科学与工程学院2.山西省太原市华北工学院材料工程系3.陕西省西安市西北工业大学材料科学与工程学院)
Abstract: With the microscopic phase-field model, the precipitation process of aged alloys was explored by computer simulation, which could clarify some discussional views on the precipitation mechanisms of alloys. The precipitation process of Ni75Al2.5V22.5 alloy was studied. From the simulated atomic pictures, calculated order parameters and volume fraction of different precipitates, it’s found that the θ ordered phase precipitates earlier than γ′ ordered phase by congruent ordering+spinodal decomposition mechanism and thus produces a nonstoicheometric θ single ordered phase. Then, the nonstoicheometric γ′ phase is precipitated by a non-classical nucleation and growth mechanism at the APBS of θ phases. Meanwhile, both of them transform to stoicheometric ordered phases.
Key words: Ni3V; Ni3Al; phase-field model; precipitation process; computer simulation