Effects of Si content and Ca modification on microstructure and thermal expansion property of Mg–Si alloys

2020 ◽  
Vol 253 ◽  
pp. 123260 ◽  
Author(s):  
Tian Guo ◽  
Shusen Wu ◽  
Xiong Zhou ◽  
Shulin Lü ◽  
Lanqing Xia
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Property ◽  
Expansion Property ◽  
Si Content

Enhanced Negative Thermal Expansion Property Deduced by the Breaks of Superstructure

2021 ◽  
Vol 13 (4) ◽  
pp. 556-562
Author(s):  
Niu Zhang ◽  
Ming-Yi Wu ◽  
Ya-Ming Liu ◽  
Meng-Jie Yang ◽  
Ming-Ju Chao ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Wide Temperature Range ◽  
Potential Application ◽  
Negative Thermal Expansion ◽  
Thermal Expansion Property ◽  
Expansion Property ◽  
Good Potential ◽  
Nested Structure

The HfV2O7/HfMo2O8 composite were prepared in situ. The phase, structure and thermal expansion property were analyzed. The results indicate the composite consist of cubic HfV2O7 and hexagonal HfMo2O8. The two types of structures were coexisted and mixed uniformly, and interacted with each other. The mutual nested structure suppressed the formation of 3×3×3 superstructure in HfV2O7 (RT) introduced by the reaction in situ. The promoted coupled rotation of quasi-rigid polyhedron units could enhance the negative thermal expansion (NTE) property. The HfV2O7/HfMo2O8 composite exhibits excellent NTE property from 250 to 673 K (at least) with CTE -3.09 × 10-6 K-1. The good NTE property and thermal stability over a wide temperature range, especially near the RT range, bring a good potential application in designing zero thermal expansion materials.

scholarly journals Substitutions of Zr4+/V5+ for Y3+/Mo6+ in Y2Mo3O12 for Less Hygroscopicity and Low Thermal Expansion Properties

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3945 ◽  
Author(s):  
Qiang Ma ◽  
Lulu Chen ◽  
Heng Qi ◽  
Qi Xu ◽  
Baohe Yuan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermal Expansion ◽  
Crystal Structures ◽  
Room Temperature ◽  
Crystal Water ◽  
Thermal Expansion Property ◽  
Expansion Property ◽  
Low Thermal Expansion ◽  
Substitution Content ◽  
Structure And Microstructure

In this investigation, ZrxY2−xVxMo3−xO12 (0 ≤ x ≤ 1.4) is developed and the effects of the substitutions of Zr4+/V5+ for Y3+/Mo6+ in Y2Mo3O12 on the hygroscopicity and thermal expansion property are investigated. For the smaller substitution content (x ≤ 0.5), their crystal structures remain orthorhombic, while there is crystal water still in the lattice. The linear coefficients of thermal expansions (CTEs), for x = 0.1, 0.3, 0.5, and 0.7, are about −4.30 × 10−6, −0.97 × 10−6, 0.85 × 10−6, and 0.77 × 10−6 K−1, respectively, from 476 to 773 K, which means that the linear CTE could be changed linearly with the substitution content of Zr4+/V5+ for Y3+/Mo6+ in Y2Mo3O12. As long as the substitution content reaches x = 1.3/1.4, almost no hygroscopicity and low thermal expansion from room temperature are obtained and are discussed in relation to the crystal structure and microstructure.

Study on Preparation of Low-Thermal Expansion Coefficient Concrete with Fly Ash

2014 ◽  
Vol 599 ◽  
pp. 89-92 ◽  
Author(s):  
Sha Ding ◽  
Zhong He Shui ◽  
Teng Pan ◽  
Wei Chen
Keyword(s):  
Thermal Expansion ◽  
Fly Ash ◽  
Pore Structure ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Cement Concrete ◽  
Thermal Expansion Property ◽  
Expansion Property ◽  
Low Thermal Expansion ◽  
Addition Level

The low-thermal expansion coefficient (CTE) of cement paste and concrete are designed and prepared with fly ash in this study. The thermal expansion property and pore structure of cement/concrete are tested by Thermal Dilatometer, MIP, and SEM. The test results show that the addition of fly ash lowers the thermal expansion rate and coefficient of hardened paste. The increase of addition level is accompanied by the decrease of the thermal expansion coefficient. The introduction of fly ash could improve the pore structure of concrete, thus improve the thermal expansion property of cement concrete.

Preparation and Negative Thermal Expansion Property of ZrWMoO8

2010 ◽  
Vol 177 ◽  
pp. 245-248
Author(s):  
Juan Yang ◽  
Qin Qin Liu ◽  
Chuang Liang Zang ◽  
Xiao Nong Cheng
Keyword(s):  
Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Mechanical Analysis ◽  
Cell Parameters ◽  
Thermal Expansion Property ◽  
In Situ Xrd ◽  
Structure And Morphology ◽  
Expansion Property ◽  
Different Temperatures

Negative thermal expansion (NTE) material ZrWMoO8 was prepared by hydrothermal method. The phase structure and morphology of the obtained precursor and final product were examined by XRD and SEM, respectively. To study its negative thermal expansion property, two methods were utilized. One is based on the in-situ XRD results and the thermal expansion coefficient (CTE) was calculated by the cell parameters obtained at different temperatures. Another is based on the thermo-mechanical analysis (TMA) and the CTE was calculated by the length of ZrWMoO8 bar at different temperatures. The differences between these two methods were also discussed.

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