【摘要】 对压力作用下沿[001]晶向极化的Pb(Mg_1/3Nb_2/3)O₃-0.32PbTiO₃（PMN-0.32PT）弛豫型铁电单晶的应力应变行为进行了实验研究,实验结果表明铁电单晶〈001〉晶向的应力应变行为和铁电多晶有本质的不同,是传统的电畴翻转机理所难以解释的,所提出的极化旋转（相变）模型合理地解释了实验中观察到的现象;基于提出的极化旋转（相变）模型,采用细观力学方法建立了铁电单晶的细观本构模型.在模型中采用黏塑性公式描述铁电单晶可能的8个相变系统的相变行为.为了验证模型的可靠性,用该模型模拟了铁电单晶〈001〉晶向的应力应变实验曲线.计算表明,该模型能较好地模拟铁电单晶〈001〉晶向的相变行为.更多还原

【Abstract】 The stress and strain properties of〈001〉oriented PMN-0.32PT relaxor ferroelectric single crystals are investigated in this paper.Obtained results show that the stress and strain behavior along〈001〉crys- tallographic direction is different from that of the ferroelectric polycrystal.Polarization rotation models are developed to explain the observed behaviors of PMN-0.32PT.Based on the experimental phase transformation mechanism of ferroelectric single crystal,a constitutive model of ferroelectric single crystal is proposed using micromechanical method.In the model,the phase transformation systems on 8 possible sliding planes are characterized by a viscoplastic law.The behavior of ferroelectric single crystal is then derived from phenomenal crystallographic theory through the transformation strain on sliding planes.The developed model is applied to simulate the experimental stress-strain curve of〈001〉oriented PMN-0.32PT.It is shown that the model can faithfully capture the key characteristics of the observed constitutive behavior of〈001〉oriented PMN-0.32PT.更多还原