First Principle Study of Mechanical Properties of Yttrium Silicates

• Main Authors: JIN Lei, CUI Xiang-zhong, WANG Chun, ZHOU Guo-dong, JIANG Chun-zhu, LI Qi-lian, YANG Jing
• Format: Article
• Language: zho
• Published: Journal of Materials Engineering 2017-07-01
• Series: Journal of Materials Engineering
• Subjects: Y₂SiO₅; Y₂Si₂O₇; first principle; mechanical property
• Online Access: http://jme.biam.ac.cn/CN/Y2017/V45/I7/48
• ISSN: 1001-4381; 1001-4381

In order to investigate mechanical properties of Y₂SiO₅ and Y₂Si₂O₇ yttrium silicates coatings on C_f/SiC composites and design thermal environment barrier coatings, first-principles calculations were performed to investigate electronic and mechanical properties of X1-Y₂SiO₅ and <i>γ</i>-Y₂Si₂O₇ using gradient generalized approximation (GGA) based on first principles. The results indicate that they are both mechanically stable structures. Bulk, shear modulus, Young's modulus of X1-Y₂SiO₅ and <i>γ</i>-Y₂Si₂O₇ are 112GPa, 49GPa, 128GPa, 0.31 and 114GPa, 55GPa, 142GPa, 0.29, respectively. These mechanical properties of X1-Y₂SiO₅ are lower than those of <i>γ</i>-Y₂Si₂O₇. At the same time, toughness, thermal expansion coefficient and residual stress of two ideal crystals were studied. The results show that X1-Y₂SiO₅ has better ductile properties than <i>γ</i>-Y₂Si₂O₇ and its thermal expansion coefficient is larger than that of <i>γ</i>-Y₂Si₂O₇ and while, the residual stress of Y₂SiO₅ is lower.