Effects of External Stresses on the Martensitic Transformation in a 3D Polycrystalline Material Using the Phase Field Me
- PDF / 1,985,358 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 18 Downloads / 170 Views
Effects of External Stresses on the Martensitic Transformation in a 3D Polycrystalline Material Using the Phase Field Method Amer Malik1, Gustav Amberg1 and John Ågren2 1 Department of Mechanics, Royal Institute of Technology, Osquars Backe 18, Stockholm, 10044, Sweden. 2 Department of Materials Science & Engineering, Royal Institute of Technology, Brinellvägen 23, Stockholm, 10044, Sweden. ABSTRACT In the current study an elasto-plastic phase field (PF) model, based on the PF microelasticity theory proposed by A.G. Khachaturyan, is used to investigate the effects of external stresses on the evolution of martensitic microstructure in a Fe-0.3%C polycrystalline alloy. The current model is improved to include the effects of grain boundaries in a polycrystalline material. The evolution of plastic deformation is governed by using a time dependent Ginzburg-Landau equation, solving for the minimization of the shear strain energy. PF simulations are performed in 2D and 3D to study the effects of tension, compression and shear on the martensitic transformation. It has been found that external stresses cause an increase in the volume fraction of the martensitic phase if they add to the net effect of the transformation strains, and cause a decrease otherwise. It has been concluded that the stress distribution and the evolution of martensitic microstructure can be predicted with the current model in a polycrystalline material under applied stresses. INTRODUCTION Martensitic transformation has widespread applications in various fields of life, concerning not only metals and alloys but also the biological systems [1]. One of the industrial applications of the martensitic formation is cold rolling in which stacks of metals are passed through rolls under controlled conditions to achieve required properties in the resulting product. One of the critical factors in adjusting the properties of the final output is the volume fraction of different transformed products such as austenite, bainite and martensite, which, if monitored and controlled closely, could enhance the properties significantly. The volume fraction can be manipulated by applying the optimum loading through the rolls and keeping the right temperature. In this work, we have performed the phase field modeling and simulation of martensitic transformation and have studied the effect of external loading on the evolution of martensitic microstructure. Recently the phase field modeling has emerged as a powerful tool to simulate the evolution of microstructure in various materials. In this study, we have used the microelasticity theory presented by Khachaturyan [2] coupled with the phase field model presented by Chen et al. [3] and Wang et al. [4] to study the effect of external loading on the evolution of martensitic microstructure in a polycrystalline material. The given model is improved to include the effect of grain boundaries in a polycrystalline structure. Plastic accommodation has also been incorporated in the model to add the effect of plasticity. 2D and 3D simulation
Data Loading...
