EXTENDED ABSTRACT: Alloy is the most widely used material for high temperature structural component, which is subjected to complex conditions. The evolution of microstructure and mechanical property under the influence of multiple factors are the theoretical basis for material design. The phase-field model based on Chan-Hilliard and Ginzburg-Landa equations shows excellent ability in describing the alloy microstructure and property. Based on the fields of lattice misfit stress, crystal defect stress, and external load stress, a crystal plastic multi-component phase-field model is developed, the component, radiation defect, and dislocation are coupled to study the evolution of precipitated phase in Ni/Co-based superalloy and stainless steel. The relationships between multi-field coupled phase transition and creep element distribution, phase evolution dynamics, and creep property are investigated.The rafting of multi-component Ni/Co-based superalloy
causes the degradation of the creep property, the continuous dynamics of the γʹ phase is the basis for the prediction of the microstructure. The relationship between γʹ phase volume fraction, particle radius, coarsening rate, and the stability of γʹ raft were found. The study of precipitated phase and creep structure evolution dynamics provides the research method and theoretical basis for the creep microstructure-property of superalloy. Based on the radiation rate theory, a multi-phasefield model including point defect and dislocation is established. The relationships between vacancy, dislocation, radiation dose, and the evolution of point defect in Fe-Cr/Fe-Cu/Fe-Cr-Al alloys are studied. With the increase of dislocation density, the annihilation of vacancy and the phase precipitation are speeded up. Under the actions of the radiation dose, the higher radiation dose rate, the precipitates reach the equilibrium composition earlier. Meanwhile, the radiation dose rate accelerates the diffusion of solute atoms, and the growth and coarsening of α′ phase is quickened. The evolution of radiation damaged microstructure provides the theoretical basis for understanding the microscopic deformation under high temperature stress and radiation.
Keywords：Alloy; Crystal plasticity; Radiation damage; Phase-field