Hygrothermal Behavior of Advanced Polymers Above Water Boiling Temperatures

2014 ◽  
Vol 136 (1) ◽  
Author(s):  
Changsoo Jang ◽  
Bongtae Han
Keyword(s):  
Thermal Expansion ◽  
Moisture Content ◽  
Coefficient Of Thermal Expansion ◽  
Measurement Data ◽  
Hybrid Procedure ◽  
Boiling Temperature ◽  
Hygrothermal Behavior ◽  
Expansion Behavior ◽  
Wide Range ◽  
Moisture Conditions

Hygroscopic and thermal expansion behavior of advanced polymers is investigated when subjected to combined high temperature and moisture conditions. An enhanced experimental–numerical hybrid procedure is proposed to overcome the limitations of the existing methods when used at temperatures above the water boiling temperature. The proposed procedure is implemented to measure the hygrothermal strains of three epoxy molding compounds and a no-filler underfill over a wide range of temperatures including temperatures beyond the water boiling temperature. The effects of moisture content on the glass transition temperature (Tg) and coefficient of thermal expansion (CTE) are evaluated from the measurement data. A formulation to predict the Tg change as a function of moisture content is also presented.

Computational modeling and relevance of numerical convergence for the investigation of thermal expansion behavior for aluminium hybrid composites

2016 ◽  
Vol 05 (02) ◽  
pp. 1650007
Author(s):  
S. A. Mohan Krishna ◽  
T. N. Shridhar ◽  
L. Krishnamurthy
Keyword(s):  
Silicon Carbide ◽  
Thermal Expansion ◽  
Hybrid Composites ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Expansivity ◽  
Numerical Convergence ◽  
Thermal Expansion Behavior ◽  
Al 6061 ◽  
Expansion Behavior ◽  
Wide Range

The thermal characterization and analysis of composite materials has been increasingly important in a wide range of applications. The coefficient of thermal expansion (CTE) is one of the most important properties of metal matrix composites (MMCs). Since nearly all MMCs are used in various temperature ranges, measurement of CTE as a function of temperature is necessary in order to know the behavior of the material. In this research paper, the evaluation of CTE or thermal expansivity has been accomplished for Al 6061, silicon carbide and graphite hybrid MMCs from room temperature to [Formula: see text]C. Aluminium-based composites reinforced with silicon carbide and graphite particles have been prepared by stir casting technique. The thermal expansivity behavior of hybrid composites with different percentage compositions of reinforcements has been investigated. The results have indicated that the thermal expansivity of different compositions of hybrid MMCs decrease by the addition of graphite with silicon carbide and Al 6061. Empirical models have been validated for the evaluation of thermal expansivity of composites. Numerical convergence test has been accomplished to investigate the thermal expansion behavior of composites.

scholarly journals Thermal Expansion Behavior in the A2M3O12 Family of Materials

Solids ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 87-107
Author(s):  
Hongfei Liu ◽  
Weikang Sun ◽  
Zhiping Zhang ◽  
La’Nese Lovings ◽  
Cora Lind
Keyword(s):  
Thermal Expansion ◽  
Physical Properties ◽  
Coefficient Of Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Future Studies ◽  
The Past ◽  
Expansion Behavior ◽  
Wide Range ◽  
Anomalous Thermal Expansion ◽  
Published Research

Over the past several decades, research on anomalous thermal expansion materials has been rapidly growing, and increasing numbers of compounds exhibiting negative thermal expansion (NTE) have been reported. In particular, compounds with formula A2M3O12 have attracted considerable attention. A2M3O12 family materials offer a wide range of possible compositions due to the chemical flexibility of the A and M sites. According to published research, more than half of them possess NTE properties. This paper reviews the range of physical properties displayed by materials in the A2M3O12 family. Research on improving material imperfections and controlling the coefficient of thermal expansion in the A2M3O12 family are systematically summarized. Finally, challenges and questions about the developments of these A2M3O12 NTE compounds in future studies are also discussed.

Investigation of fatigue behavior of centrifuged series 3000 Al with addition of 26 wt% Cu

2020 ◽  
Vol 234 (10) ◽  
pp. 1375-1385
Author(s):  
Aref Mehditabar ◽  
Seyed E Vahdat ◽  
Gholam-Hossein Rahimi
Keyword(s):  
Electron Microscopy ◽  
Thermal Expansion ◽  
High Performance ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Fatigue Behavior ◽  
Centrifugal Casting ◽  
Image Analyzer ◽  
Casting Technique ◽  
Wide Range

More than 70% of mechanical parts in a wide range of engineering fields fail by fatigue. In addition, centrifugal casting is identified as the most effective casting technique for production of high performance cylindrical parts. In this regard, the present work aims to investigate the fatigue behavior of series 3000 Al with addition of 26 wt% Cu produced through horizontal centrifugal casting method. Microstructure characterizations are precisely studied using scanning transmission electron microscopy and field emission scanning electron microscopy in conjunction with image analyzer software. Also, compressive behavior, hardness, coefficient of thermal expansion, and wear rate ( Wr) are measured applying Zwick Z100, Vickers hardness, DIL 805A/D, and pin-on-disc machines, respectively. The results indicate that the main intermetallic compound is Al2Cu-based particle, and a volume fraction of 31 vol.% is obtained. Besides, the compressive strength of 460 MPa, elastic modulus of 10.986 GPa, hardness of 152 HV, coefficient of thermal expansion of 1.7 × 10−5 1/°C, and wear resistance of 3.3 × 10−6 g/mm2 are measured. Finally, the four-point bending fatigue test is performed and the fatigue ratio of 0.109 at about 106 cycles to failure is obtained.

Thermal Expansion Behavior and Characteristic of SiCp/Al Composites

2011 ◽  
Vol 287-290 ◽  
pp. 658-661 ◽  
Author(s):  
Xian Liang Zhou ◽  
Duo Sheng Li ◽  
Ai Hua Zou ◽  
Xiao Zhen Hua ◽  
Zhi Guo Ye ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Size Range ◽  
Coefficient Of Thermal Expansion ◽  
Pure Aluminum ◽  
Annealing Process ◽  
Ceramic Mold ◽  
Range Space ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior ◽  
Al Matrix

SiCp/Al composites were fabricated by ceramic mold freedom infiltration and pressureless infiltration, respectively. The microstructure and phases are analyzed by metallurgical microscope and coefficient of thermal expansion of SiCp/Al composites were tested by thermal dilatometer. The results show that SiCp/Al composites are compact and uniform. SiC particles were dispersed uniformly in Al matrix, and SiCp segregation was not found in composites. Under a certain SiCp size range, space between SiCp decreases with decreasing of SiCp size, and CTE of SiCp/Al composites also decreases with decreasing of particles size. Compared with CTE of composite with pure aluminum as matrix, CTE of composite with ZL101 as matrix is less. Under the annealing process, CTE of SiCp/Al composites with ZL101 as matrix is less than that with the solution and aging, which indicated that its dimensional stability of resisting to temperature fluctuation is better, and thermal expansion behavior and characteristic of SiCp/Al composites are also better.

scholarly journals Evaluation of the coefficient of thermal expansion of human and bovine dentin by thermomechanical analysis

2012 ◽  
Vol 23 (1) ◽  
pp. 03-07 ◽  
Author(s):  
Murilo Baena Lopes ◽  
Zhuoqun Yan ◽  
Simonides Consani ◽  
Alcides Gonini Júnior ◽  
Anderson Aleixo ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Third Molar ◽  
Weight Changes ◽  
Incisor Tooth ◽  
Test Environment ◽  
Material Interface ◽  
Human Teeth ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior

The mismatch of thermal expansion and contraction between restorative materials and tooth may cause stresses at their interface, which may lead to microleakage. The present work compared the coefficient of thermal expansion (CTE) with the thermomechanical behavior of human and bovine teeth and determined if the CTE is a suitable parameter to describe tooth behavior. Fifteen human third molar and 15 bovine incisor tooth slices (6×5×2 mm) were allocated to 3 groups according to the test environment: G1 - room condition, G2 - 100% humidity, G3 - desiccated and tested in dry condition. Each specimen was weighed, heated from 20 to 70ºC at 10ºC min−1 and reweighed. The CTE was measured between 20 and 50ºC. Fresh dentin (human -0.49% ± 0.27, bovine -0.22% ± 0.16) contracted on heating under dry condition. Under wet conditions, only human teeth (-0.05% ± 0.04) showed contraction (bovine 0.00% ± 0.03) accompanied by a significantly lower (p<0.05) weight loss than in dry specimens (human 0.35% ± 0.15, bovine 0.45% ± 0.20). The desiccated dentin expanded on heating without obvious weight changes (0.00% ± 0.00). The CTE found was, respectively, in dry, wet and dissected conditions in ºC-1: human (-66.03×10-6, -6.82×10-6, 5.52×10-6) and bovine (-33.71×10-6, 5.47×10-6, 4.31×10-6). According to its wet condition, the dentin showed different CTEs. The thermal expansion behavior of human and bovine dentin was similar. A simple evaluation of the thermal expansion behavior of tooth structure by its CTE value may not be appropriate as a meaningful consideration of the effects on the tooth-material interface.

scholarly journals Micro-structured medium with large isotropic negative thermal expansion

2019 ◽  
Vol 475 (2232) ◽  
pp. 20190468 ◽  
Author(s):  
Luigi Cabras ◽  
Michele Brun ◽  
Diego Misseroni
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Simple Relation ◽  
Space Structures ◽  
New Class ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Innovative Materials ◽  
New Generation

A challenge in nano- and micro-mechanics is the realization of innovative materials exploiting auxetic behaviour to tailor thermal expansion properties. For this purpose, a new class of micro-structured media possessing an extremely wide range of tunable (positive, negative or even zero) thermal expansion is proposed and analytically and experimentally assessed. For this class of isotropic Mechanical-Auxetic Thermal-Shrinking media, the effective coefficient of thermal expansion is explicitly linked to two microstructural variables via a simple relation, allowing the design with desired values. The theoretical predictions for the negative thermal properties are fully validated by the experimental and numerical outcomes. The simplicity of the proposed structure makes the design useful for the production of a new generation of advanced media, with applications ranging from micromechanical devices to large civil and space structures.

scholarly journals Effects of added SiO2 nanoparticles on the thermal expansion behavior of shape memory polymer nanocomposites

2018 ◽  
Vol 30 (1) ◽  
pp. 32-44 ◽  
Author(s):  
Mohammad Javad Mahmoodi ◽  
Mohammad Kazem Hassanzadeh-Aghdam ◽  
Reza Ansari
Keyword(s):  
Thermal Expansion ◽  
Shape Memory ◽  
Polymer Nanocomposites ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Shape Memory Polymer ◽  
Polymer Nanocomposite ◽  
Thermal Expansion Behavior ◽  
Interphase Region ◽  
Expansion Behavior

In this study, a unit cell–based micromechanical approach is proposed to analyze the coefficient of thermal expansion of shape memory polymer nanocomposites containing SiO2 nanoparticles. The interphase region created due to the interaction between the SiO2 nanoparticles and shape memory polymer is modeled as the third phase in the nanocomposite representative volume element. The influences of the temperature, volume fraction, and diameter of the SiO2 nanoparticles on the thermal expansion behavior of shape memory polymer nanocomposite are explored. It is observed that the coefficient of thermal expansion of shape memory polymer nanocomposite decreases with the increase in the volume fraction up to 12%. Also, the results reveal that with the increase in temperature, the shape memory polymer nanocomposite coefficient of thermal expansion linearly increases. The role of interphase region on the thermal expansion response of the shape memory polymer nanocomposite is found to be very important. In the presence of interphase, the reduction in nanoparticle diameter leads to lower coefficient of thermal expansion for shape memory polymer nanocomposite, while the variation of nanoparticles diameter does not affect the coefficient of thermal expansion in the absence of interphase. Based on the simulation results, the shape memory polymer nanocomposite coefficient of thermal expansion decreases as the interphase thickness increases. In addition, the contribution of interphase coefficient of thermal expansion to the shape memory polymer nanocomposite coefficient of thermal expansion is more significant than that of interphase elastic modulus.

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