High temperature plasticity of polycrystalline Galfenol (Fe-Ga)

摘要

Galfenol (Fe-Ga) is a promising and mechanically robust magnetostrictive actuator material. However, due to its high conductivity, it needs to be in thin sheet form to avoid excessive eddy current losses. Work is underway to develop conventional rolling processes to produce large quantities of thin Galfenol sheet, while retaining a preferred < 100 > crystallographic texture to optimize magnetostrictive performance. Knowledge of high temperature polycrystalline plasticity is crucial to understanding formability and crystallographic texture evolution during rolling. The deformation behavior of polycrystalline Galfenol at high temperatures was studied. Preliminary results suggest that significant dynamic recovery and/or recrystallization occur during deformation, resulting in a random texture. In-situ neutron diffraction experiments are being developed to obtain qualitative and quantitative information on the high temperature plane strain deformation of Galfenol. These experiments will be used to identify the slip systems that contribute to plastic deformation, and their dependence on temperature. Simultaneously, models of large-scale polycrystal plasticity are being developed to predict internal strains and texture evolution during deformation, which will be validated against the data obtained from the neutron diffraction experiments. Ultimately, the models will be used to develop thermo-mechanical treatments to optimize texture evolution during rolling.