Enhanced thermal expansion by micro-displacement amplifying mechanical metamaterial

MRS Advances ◽  
2018 ◽  
Vol 3 (8-9) ◽  
pp. 405-410 ◽  
Author(s):  
Lingling Wu ◽  
Bo Li ◽  
Ji Zhou
Keyword(s):  
Thermal Expansion ◽  
Amplification Factor ◽  
Coefficient Of Thermal Expansion ◽  
Science And Engineering ◽  
Thermal Expansion Property ◽  
Expansion Property ◽  
Simulation And Experiment ◽  
Simulation Results ◽  
Amplification Mechanism ◽  
Large Coefficient

ABSTRACTIt is important to achieve materials with large coefficient of thermal expansion in science and engineering applications. In this paper, we propose an experimentally-validated metamaterial approach to amplify the thermal expansion of materials based on the guiding principles of flexible hinges and displacement amplification mechanism. The thermal expansion property of the designed metamaterial is demonstrated by simulation and experiment with a temperature increase of 245 K for the two-dimensional sample. Both experimental and simulation results display amplified thermal expansion property of the metamaterial. The effective coefficient of thermal expansion of the metamaterials is demonstrated to be dependent on the size parameters of the structure, which means by appropriately tailoring these parameters, the thermal expansion of materials could be amplified with different amplification factor. This work provides an important method to control the thermal expansion coefficient of materials and could be applied in various industry domain.

Effect of Forming Pressure and Sintering Temperature on Thermal Expansion Property of Li2O-Al2O3-P2O5-SiO2 Glass-Ceramics

2011 ◽  
Vol 197-198 ◽  
pp. 436-439
Author(s):  
Min Hua Luo ◽  
Zhuo Hao Xiao
Keyword(s):  
Thermal Expansion ◽  
Sintering Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Thermal Expansion Property ◽  
Expansion Property ◽  
Prepared Glass

Li2O-Al2O3-P2O5-SiO2 xerogel powders were synthesized by sol-gel route and glass-ceramics were prepared under different forming pressure and sintering temperature. The effects of sintering temperature and forming pressure on coefficient of thermal expansion of prepared glass-ceramics were investigated by means of DTA-TG, TEC and XRD. The results indicate that xerogel powders crystallization begins at 785°C, and the main crystallite phases in the researched specimens are virgilite and cristobalite. The TEC decreases linearly with the forming pressure. When the sintering temperature is 950°C and forming pressure is 40MPa, a low TEC of 0.65×10-6 °C-1 can be obtained.

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.

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