The main attention of this paper was devoted to the study of the effect of different cooling rates on the magnetic domain configuration and magnetostrictive behavior of heat-treated Fe-15 at% Ga alloy. After annealing...The main attention of this paper was devoted to the study of the effect of different cooling rates on the magnetic domain configuration and magnetostrictive behavior of heat-treated Fe-15 at% Ga alloy. After annealing at 1,000℃ for 3 h, the samples were subjected to water quenching, air cooling, and furnace cooling treatments. Phase constitution and magnetic domain structures of the samples were studied using X-ray diffraction （XRD） and magnetic force microscopy （MFM）. XRD results indicate a single phase of α-Fe with disordered bcc （A2） structure for all samples. MFM results show that both water-quenched （WQ） and air-cooled （AC） samples are mainly made from ordered stripe domain structures, whereas a mixture of irregular stripe, zigzag, and plate domain patterns are observed in furnace-cooled （FC） sample. Magnetostrictive strain was measured in the presence of an extemally applied magnetic field. It is found that WQ sample has the highest magnetostriction, while AC and FC samples exhibit moderate and the lowest magnetostriction, respectively, against the applied field. The dependence of initial domain configurations on thermal history is found to be conducive to the change in saturation magnetostrictions of the samples.展开更多
The hysteresis nonlinearity of giant magnetostrictive actuator(GMA) is stress-dependent.In this paper,laboratory experiments were performed to characterize the stress-dependent hysteresis properties of a GMA under dif...The hysteresis nonlinearity of giant magnetostrictive actuator(GMA) is stress-dependent.In this paper,laboratory experiments were performed to characterize the stress-dependent hysteresis properties of a GMA under different compressive stresses ranging from ?11.3 MPa to ?24.3 MPa and harmonic current excitation with amplitudes from 0.6 A to 1.2 A.The experimental results showed that remarkable changes in peak-peak displacement responses,hysteresis loop width and hysteresis loss occurred with the increasing of compressive stress;no significant changes in coercive current were observed.Based on the analysis of experimental data and discussion of the influences of the weights of Modified Prandtl-Ishlinskii(MPI) on the characteristics of hysteresis loops,a stress-dependent Prandtl-Ishlinskii(SDPI) model was proposed by extending the MPI model to describe the effects of compressive stress,in which the weights of deadzone operators are extended as function of compressive stress.Good agreements were obtained between the model simulation results and the experimental data.Additional model validations were given by the performances of tracking control experiments with an inverse feedforward controller.The experimental results have clearly shown that the inverse SDPI is effective for compensating stress-dependent hysteresis including major and minor loops.展开更多
基金the support of Center of Excellence for High Performance Materials(CEPMAT)at University of Tehran for providing vacuum arc melting
文摘The main attention of this paper was devoted to the study of the effect of different cooling rates on the magnetic domain configuration and magnetostrictive behavior of heat-treated Fe-15 at% Ga alloy. After annealing at 1,000℃ for 3 h, the samples were subjected to water quenching, air cooling, and furnace cooling treatments. Phase constitution and magnetic domain structures of the samples were studied using X-ray diffraction （XRD） and magnetic force microscopy （MFM）. XRD results indicate a single phase of α-Fe with disordered bcc （A2） structure for all samples. MFM results show that both water-quenched （WQ） and air-cooled （AC） samples are mainly made from ordered stripe domain structures, whereas a mixture of irregular stripe, zigzag, and plate domain patterns are observed in furnace-cooled （FC） sample. Magnetostrictive strain was measured in the presence of an extemally applied magnetic field. It is found that WQ sample has the highest magnetostriction, while AC and FC samples exhibit moderate and the lowest magnetostriction, respectively, against the applied field. The dependence of initial domain configurations on thermal history is found to be conducive to the change in saturation magnetostrictions of the samples.
基金supported by the National Natural Science Foundation of China (Grant Nos. 91016006 and 91116002)the Fundamental Research Funds for the Central Universities
文摘The hysteresis nonlinearity of giant magnetostrictive actuator(GMA) is stress-dependent.In this paper,laboratory experiments were performed to characterize the stress-dependent hysteresis properties of a GMA under different compressive stresses ranging from ?11.3 MPa to ?24.3 MPa and harmonic current excitation with amplitudes from 0.6 A to 1.2 A.The experimental results showed that remarkable changes in peak-peak displacement responses,hysteresis loop width and hysteresis loss occurred with the increasing of compressive stress;no significant changes in coercive current were observed.Based on the analysis of experimental data and discussion of the influences of the weights of Modified Prandtl-Ishlinskii(MPI) on the characteristics of hysteresis loops,a stress-dependent Prandtl-Ishlinskii(SDPI) model was proposed by extending the MPI model to describe the effects of compressive stress,in which the weights of deadzone operators are extended as function of compressive stress.Good agreements were obtained between the model simulation results and the experimental data.Additional model validations were given by the performances of tracking control experiments with an inverse feedforward controller.The experimental results have clearly shown that the inverse SDPI is effective for compensating stress-dependent hysteresis including major and minor loops.
