材料期刊网

Molecular dynamics simulation for grain boundary deformation under tensile loading condition

Youngsuk Kim , Dongyoul Choi , Sungyeun Won

材料科学技术（英文）

In this study, MD simulations have been performed to observe the behavior of a grain boundary in an alpha -Fe plate under 2-dimensional loading. In MD simulation, the acceleration of every molecule can be achieved from the potential energy and the force interacting between each molecule, and the integration of the motion equation by using Verlet method gives the displacement of each molecule. Initially, four α-Fe rectangular plates having different misorientation angles of grain boundary were modeled by using the Johnson potential and Morse potential. We compared the potential energy of the grain boundary system with that of the perfect structure model. Also, we could obtain the width of the grain boundary by investigating the local potential energy distribution. The tensile loading for each grain boundary models was applied and the behavior of grain boundary was studied. From this study it was clarified that in the case using Johnson potential, the obvious fracture mechanism occurs along the grain boundary, in the case of Morse potential, the diffusion of the grain boundary appears instead of the grain boundary fracture.

关键词:

Prediction and improvement of mechanical properties of corrosion resistant superalloy K44 with adjusting minor additions C, B and Hf

Materials Transactions

The neural network (NN) method is applied to predict the influence of minor additions C, B and Won mechanical properties of cast superalloy K44 with heat treatment parameters considered. Furthermore, the influence of minor additions C B and Hf on phase stability is estimated using d-electrons theory. The results from these two methods indicate that decreasing C content, increasing B content and doping 0.2-0.3 mass% Hf can balance the desired mechanical properties and phase stability in K44 alloy, which also is confirmed experimentally through the relation between mechanical properties and phase stability of base/modified K44 alloys.

关键词: superalloy K44;neural network;d-electrons theory;mechanical;properties;phase stability;bayesian neural-network;nickel-base superalloys;creep-rupture life;behavior;phase