Bendersky L A, Roytburd A, Boettinger W J
National Institute of Standards and Technology, Gaithersburg, MD 20899-0001.
Dept. of Materials and Nuclear Engineering, University of Maryland, College Park, MD 20742.
J Res Natl Inst Stand Technol. 1993 Sep-Oct;98(5):561-583. doi: 10.6028/jres.098.038.
Possible paths for the constant composition coherent transformation of BCC or B2 high temperature phases to low temperature HCP or Orthorhombic phases in the Ti-Al-Nb system are analyzed using a sequence of ciystallographic structural relationships developed from subgroup symmetry relations. Symmetry elements lost in each step of the sequence determine the possibilities for variants of the low symmetry phase and domains that can be present in the microstructure. The orientation of interdomain interfaces is determined by requiring the existence of a strain-free interface between the domains. Polydomain structures are also determined that minimize elastic energy. Microstructural predictions are made for comparison to experimental results given by Benderslcy and Boettinger [J. Res. Natl. Inst. Stand. Technol. 98, 585 (1993)].
利用从子群对称关系发展而来的一系列晶体结构关系，分析了Ti-Al-Nb体系中体心立方（BCC）或B2高温相恒组成相干转变为低温六方密堆积（HCP）或正交相的可能路径。该序列中每一步失去的对称元素决定了低对称相变体和微观结构中可能存在的畴的可能性。畴间界面的取向由畴间存在无应变界面的要求确定。还确定了使弹性能最小化的多畴结构。进行微观结构预测，以便与Benderslcy和Boettinger [《美国国家标准与技术研究院研究杂志》98, 585 (1993)]给出的实验结果进行比较。
