An aqueous magnetorheological fluid (MRF) was prepared with carbonyl iron powders as magnetic particles. Rheological behaviors of the MRF both in on-state and off-state were measured, and the measured results were fitted with Bingham model, Casson model and shear-thinning relationship, respectively. Also the responding relationship bewteen yield shear stress and magnetic field strength was discussed. It was found that both the Bingham and Casson model could well describe rheological behaviors of the MRF, and both shear stress and apparent viscosity increase markedly in on-state, with increasing yield shear stress from about 2 Pa to about 80 kPa, and increasing apparent viscosity at shear rate 50 s-1 from about 64 mPa·s to about 1600 Pa·s. There was a exponential relationship between yield shear stress and magnetic field strength, with the exponent about 1.7~1.8.% 制备了羰基铁粉为磁性颗粒的水基磁流变液.分别测定了该磁流变液磁场作用下的流变行为及零场流变行为,并采用Bingham模型和Casson模型及剪切稀化关系对获得的流变行为进行了拟合计算,探讨了磁流变液的剪切屈服强度和磁场强度之间的响应关系.研究表明,Bingham模型和Casson模型均可较好地描述磁流变液的流变行为；磁场作用下,磁流变液的剪切应力和表观粘度显著增高,剪切屈服强度从约2Pa 增大到约80kPa；剪切率为50s-1时的表观粘度从约64mPa·s增加到约1600Pa·s；该磁流变液的剪切屈服强度与磁场强度之间存在指数关系,其值约为1.7~1.8.
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