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结合作者提出的形状记忆因子的概念,阐述了形状记忆合金(SMA)超弹性和形状记忆效应的微观机理,将SMA的超弹性和形状记忆效应统一归结为形状记忆效应.重新定义了形状记忆因子,并明确了其物理意义.利用SMA在相变过程中马氏体体积分数和相变自由能间的微分关系,建立了描述SMA相变行为的形状记忆演化方程.该形状记忆演化方程能同时考虑相变峰值温度、相变开始和结束温度对SMA相变行为的影响,并能描述SMA从孪晶马氏体向非孪晶马氏体的转变过程,克服了现存SMA相变方程或形状记忆方程的局限性,能更全面准确地描述SMA的相变行为.从宏观力学角度,建立了能全面描述SMA实现形状记忆效应的热力学本构方程,在假设SMA为各向同性材料的基础上,将该本构方程从一维推广到三维.该本构方程中的所有材料参数都可以通过宏观实验测定,比现存三维本构方程更便于工程实际应用.
Combined with the concept of shape memory factor proposed by the author, the microscopic mechanism of the hyperelasticity and shape memory effect of shape memory alloy (SMA) is elaborated, and the superelasticity and shape memory effect of SMA are summed up as shape memory effect.The shape memory factor , And its physical meaning is clarified.The shape memory evolution equation describing the SMA phase transition behavior is established by using the differential relationship between martensite volume fraction and phase transition free energy of SMA during phase transition.The shape memory evolution equation can simultaneously Considering the influence of phase transition peak temperature, phase change start and end temperature on SMA phase transition behavior, and can describe the transition process of SMA from twin martensite to non-twin martensite, overcoming the existing SMA phase change equation or shape The limitations of the memory equation can describe the phase transition behavior of SMA more completely and accurately.According to macroscopic mechanics, a constitutive equation of thermodynamics that can describe SMA shape memory effect is established. Based on the assumption that SMA is an isotropic material , The constitutive equation is generalized from one dimension to three dimensions.All the material parameters in the constitutive equation can be determined by macroscopic experiments and more convenient than the existing three-dimensional constitutive equations Cheng practical application.