External field in the Landau theory of a weakly discontinuous phase transition: Pressure effect in the martensitic transitions.
External field in the Landau theory of a weakly discontinuous phase transition: Pressure effect in the martensitic transitions.
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弱不连续相变朗道理论中的外场：马氏体转变中的压力效应。
DOI：
10.1103/physrevb.50.16326
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Fradkin
中科院分区：
文献类型：
--
作者：
Fradkin
考虑了静水压力和单轴压力对立方晶体中适当的铁弹性（马氏体）相变的影响。体积应变被认为是与对称剪切应变共轭的二阶参数，该剪切应变控制点对称性简化为四方对称性。分析了吉布斯自由能的金兹堡-朗道展开中的相应项的一阶和二阶跃迁。研究了压力对转变温度以及等温压缩性异常和线性热膨胀系数的影响，并讨论了 V 3 Si、In-Tl 和 Ni-Al 热膨胀异常的最新实验数据。人们发现，热膨胀的非线性意味着剪切应变和体积变化之间存在一种特殊关系，这种关系可能导致从 fcc 晶格转变为 bcc 晶格，正如在铁合金中观察到的那样。
The effect of hydrostatic as well as uniaxial pressure upon proper ferroelastic (martensitic) phase transitions in cubic crystals is considered. The volumetric strain is considered to be the secondary order parameter conjugated to the symmetrized shear strain that governs the reduction of point symmetry to a tetragonal one. Corresponding terms in the Ginzburg-Landau expansion of the Gibbs free energy are analyzed for transitions of the first as well as of the second order. The pressure effect on the transition temperature as well as on the anomalies of isothermal compressibility and the linear thermal-expansion coefficient are studied and recent experimental data on thermal expansion anomalies in V 3 Si, In-Tl, and Ni-Al are discussed. The nonlinearity of thermal expansion is found to imply a special relation between the shear strain and volume change that can lead to the transformation from a fcc lattice to a bcc one, as observed in the iron alloys.