钇硅酸盐材料力学性能的第一性原理研究

发布时间：2018-02-03 03:37

本文关键词： YSiO YSiO 第一性原理力学性能　出处：《材料工程》2017年07期 　论文类型：期刊论文

【摘要】：为深入研究C_f/SiC复合材料钇硅酸盐涂层材料Y_2SiO_5与Y_2Si_2O_7的力学性能,为钇硅酸盐涂层体系的设计提供理论依据,基于第一性原理广义梯度近似,研究钇硅酸盐理想晶体X1-Y_2SiO_5和γ-Y_2Si_2O_7的电子结构、力学性能。结果表明:X1-Y_2SiO_5和γ-Y_2Si_2O_7均为机械稳定结构,X1-Y_2SiO_5与γ-Y_2Si_2O_7的体模量、剪切模量、弹性模量、泊松比分别为112,49,128GPa,0.31和114,55,142GPa,0.29。可见X1-Y_2SiO_5的模量较γ-Y_2Si_2O_7低。同时研究二者理想晶体的韧性、热膨胀系数、残余应力。结果表明:X1-Y_2SiO_5韧性较γ-Y_2Si_2O_7好,热膨胀系数较γ-Y_2Si_2O_7高,残余应力较γ-Y_2Si_2O_7低。
[Abstract]:In order to study the mechanical properties of yttrium silicate coating material Ys _ 2SiO _ 5 and Ys _ 2Si _ 2O _ 7, the theoretical basis for the design of yttrium silicate coating system is provided. Based on the first-principle generalized gradient approximation, the electronic structures of yttrium silicate ideal crystals X _ 1-Ys _ 2SiO _ s _ 5 and 纬 -Y _ s _ 2Si _ 2O _ O _ 2O _ 7 are studied. Mechanical properties. The results show that the structure of 1: X _ 1-Y _ S _ 2SiO _ 5 and 纬 -Y _ Y _ 2Si _ 2O _ 7 are mechanically stable. The bulk modulus, shear modulus, elastic modulus and Poisson's ratio of X _ 1-Y _ 2SiO _ 5 and 纬 -Y _ 2SiO _ 2O _ 7 are 0.31 and 114 respectively. It can be seen that the modulus of X1-Y2SiO5 is lower than that of 纬 -Y2Si2O7. At the same time, the toughness and thermal expansion coefficient of the two ideal crystals are studied. Residual stress. The results show that the toughness of 1% X _ 1-Y _ S _ 2SiO _ 5 is better than that of 纬 -Y _ Y _ 2Si _ 2O _ 7, and the coefficient of thermal expansion is higher than that of 纬 -Y _ T _ 2Si _ 2O _ 7. The residual stress is lower than that of 纬 -Y2Si2SiS _ 2Si _ 2O _ 7.
【作者单位】：北京航空制造工程研究所高能束流加工技术重点实验室;
【基金】：北京航空制造工程研究所基金(201510407)
【分类号】：TB306
【正文快照】： Cf/SiC复合材料已成功用于喷管、推力室等发动机高温部件。但Cf/SiC复合材料工程化应用主要瓶颈问题是其高温抗氧化性能差。表面涂层法是复合材料实现高温长时抗氧化的主要方法[1]。目前,表面涂层材料经历了莫来石、Si-W系[2]、Si-Mo系[3,4]等不同的发展历程。近年来,硅酸钇系

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