Mean and Instantaneous Thermal Expansion of Uncoated and Ti Coated Diamond/Copper Composite Materials

2013 ◽  
Vol 702 ◽  
pp. 202-206 ◽  
Author(s):  
Qing Yun Wang ◽  
Wei Ping Shen ◽  
Ming Liang Ma

Heat sink materials not only should have higher thermal conductivity, but also have smaller difference of thermal expansion with cooled material. diamond/copper composites were made by the powder metallurgy method. Vacuum slowly vapor deposition technique was employed to deposit a titanium film on diamond particles before mixing with Cu powder in order to improve the bonding strength between Cu and diamond particles during sintering. The thermal expansion of diamond/Cu d composite was measured in the temperature range from 50 to 600 °C. The results show that the titanium film on diamond improves the interfacial bonding and reduces the coefficient of thermal expansion (CTE) of Cu/diamond composites. The CTE of diamond/Cu composites decreases with increasing diamond volume fraction as the results of mixture rule and the intense restriction effect of diamond reinforcement on the copper matrix. The residual stresses and pores in the composites affect instantaneous thermal expansion of diamond/Cu composites.

Author(s):  
Preetkanwal Singh Bains ◽  
H. S. Payal ◽  
Sarabjeet Singh Sidhu

The present study investigates the thermal conductivity and coefficient of thermal expansion of bimodal SiCp reinforced Aluminum matrix composites formed via powder metallurgy method. The after-effects of proportion of particulate reinforcement as size distribution and sintering parameters on the thermal properties have been explored. The Box-Behnken design for response surface methodology was adopted to recognize the significance of chosen variables on the thermal conductivity and coefficient of thermal expansion of the composite. It is witnessed that the thermal conductivity and coefficient of thermal expansion enhanced due to increase in fine SiC particulates volume fraction. It has been exhibited that the fine SiC particulates (37μm) doped Al-matrix occupied interstitial positions and developed continuous SiC-matrix network. SEMs were conducted to evaluate the microstructure architecture for MMCs.


2013 ◽  
Vol 594-595 ◽  
pp. 857-861
Author(s):  
K. Azmi ◽  
M.N. Derman ◽  
A.M. Mustafa Al Bakri ◽  
A.V. Sandu

The introduction of the metal matrix composites as the advanced electronic packaging materials is highly anticipated because their thermal properties can be engineered to match those of semiconductors, ceramics substrates and optical fibers. Among these advanced packaging materials, silicon carbide particles reinforced copper matrix (Cu-SiCp) composites are highly rated due to the high thermal conductivity of copper and low coefficient of thermal expansion (CTE) of silicon carbide. However, the Cu-SiCp composites fabricated via the conventional powder metallurgy (PM) technique usually have immature thermophysical properties due to the weak bonding between the copper matrix and the SiCp reinforcement. In order to improve the bonding between the two constituents, the SiCp were coated with copper via electroless coating process prior to PM fabrication processes. Based on the experimental results, The CTE and porosity of the Cu-SiCp composites were significantly affected by the volume fraction of SiCp. Furthermore, the CTE and porosity of the Cu-Coated Cu-SiCp composites were significantly lower than the non-Coated Cu-SiCp composites. These differences were mainly contributed by the nature of the bonding between the copper matrix and SiCp reinforcement.


Author(s):  
Aref Mehditabar ◽  
Seyed E Vahdat ◽  
Gholam-Hossein Rahimi

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.


Author(s):  
Xiaolong Shi ◽  
Mohammad Kazem Hassanzadeh Aghdam ◽  
Reza Ansari

The objective of this work is to investigate the coefficient of thermal expansion of carbon nanotube reinforced aluminum matrix nanocomposites in which aluminum carbide (Al4C3) interphase formed due to chemical interaction between the carbon nanotube and aluminum matrix is included. To this end, the micromechanical finite element method along with a representative volume element, which incorporates, carbon nanotube, interphase, and aluminum matrix is employed. The emphasis is mainly placed on the effect of Al4C3 interphase on the coefficient of thermal expansion of aluminum nanocomposites with random microstructures. The effects of interphase thickness, carbon nanotube diameter, and volume fraction on the thermomechanical response of aluminum nanocomposite are discussed. The results reveal that the effect of Al4C3 interphase on the coefficient of thermal expansion of the aluminum nanocomposites becomes more significant with (i) increasing the coefficient of thermal expansion volume fraction, (ii) decreasing the coefficient of thermal expansion diameter, and (iii) increasing the interphase thickness. It is clearly observed that the coefficient of thermal expansion varies nonlinearly with the carbon nanotube diameter; however, it decreases linearly as the carbon nanotube volume fraction increases. Furthermore, the axial and transverse coefficient of thermal expansions of aligned continuous and discontinuous carbon nanotube-reinforced aluminum nanocomposites with Al4C3 interphase are predicted. Also, the presented finite element method results are compared with the available experiment in the literature, rule of mixture, and concentric cylinder model results.


2018 ◽  
Vol 30 (1) ◽  
pp. 32-44 ◽  
Author(s):  
Mohammad Javad Mahmoodi ◽  
Mohammad Kazem Hassanzadeh-Aghdam ◽  
Reza Ansari

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.


2012 ◽  
Vol 620 ◽  
pp. 208-212
Author(s):  
Mohamd Nur Fuadi Pargi ◽  
Pei Leng Teh ◽  
Salmah Husseinsyah ◽  
Cheow Keat Yeoh

The effect of recycled copper filled epoxy composites on thermal, electrical and physical properties were investigated. The recycled copper was collected as a waste from the milling machine. The recycled copper filled epoxy composite was mixed using mechanical stirrer. The effect of volume fraction of recycled copper of the epoxy composites were studied based on the coefficient of thermal expansion (CTE), electrical conductivity hardness and density. Incorporation of recycled copper has decreased the CTE of the composites. The electrical conductivity, hardness and density of the composites increased with increasing of volume fraction and filler loading.


2020 ◽  
Vol 54 (13) ◽  
pp. 1761-1781
Author(s):  
SA Pottigar ◽  
B Santhosh ◽  
RG Nair ◽  
P Punith ◽  
PJ Guruprasad ◽  
...  

Three-dimensional braided composites with zero, negative and isotropic coefficient of thermal expansion are presented based on an analytical homogenization technique. The configuration of the braided composites is worked out considering the exact jamming condition leading to higher fiber volume fraction. A total of four configurations of three-dimensional-braided composite representative unit cells were analyzed. Among these, two arrangements are 4-axes and the other two are 5-axes. Special emphasis is given on the detailed description of the representative unit cells. Analysis reveals that a three-dimensional-braided composite configuration with thermoelastic isotropic properties having same coefficient of thermal expansion along x-, y-, and z-axes is achievable. As a special case, the homogenization model is used to predict, for the first time, a configuration of braided architecture and material leading to zero coefficient of thermal expansion along x-, y- and z-directions.


2011 ◽  
Vol 399-401 ◽  
pp. 315-319 ◽  
Author(s):  
Sheng Li Lv ◽  
Qing Na Zeng ◽  
Lei Jiang Yao ◽  
Xiao Yan Tong

The aim of this paper is to propose a microstructure modeling for prediction of thermal conductivity of plain weave C/SiC fibre bundles considering manufacturing flaws. Utilizing photomicrographs taken by scanning electron microscope (SEM), we established an accurate sub representative volume element (sub-RVE) model for carbon fiber bundles and RVE for the plain weave C/SiC composite with consideration of four classes of manufacturing porosity. The thermal expansion coefficient of carbon fibre bundles on axial and transverse coefficient of thermal expansion is calculated, respectively. Based on which thermal expansion coefficient of plain weave C/SiC is obtained with the value of 2.71×10-6 in-plain, which has a good correlation with experimental value. The influences of different manufacturing flaws on material’s thermal expansion coefficient are studied. The study shows that as the matrix porosity or crack volume fraction is increasing, thermal expansion coefficient of plain weave C/SiC is decreasing correspondingly while the speed gradually slows.


Author(s):  
Mohammad K Hassanzadeh-Aghdam

Understanding the structure–property relations for metal matrix nanocomposites reinforced with nanoparticles is a key factor for a reliable and optimal design of such new material systems. In the present study, coefficient of thermal expansion of silicon carbide (SiC) nanoparticle-reinforced aluminum (Al) matrix nanocomposites is predicted using a three-dimensional unit cell based micromechanical approach. The model takes into account the aluminum carbide (Al4C3) interphase region formed due to the reaction between SiC nanoparticles and surrounding Al matrix. The effects of some critical parameters, including volume fraction and diameter of SiC nanoparticles, interphase features such as geometry and material properties on the coefficient of thermal expansion of Al nanocomposite are extensively investigated. The obtained results clearly reveal the high influence of the interphase region on the coefficient of thermal expansion of Al nanocomposite. Based on the simulation results, the coefficient of thermal expansion of Al nanocomposite nonlinearly decreases with the increase in the interphase thickness or decreasing SiC nanoparticles diameter. Furthermore, the role of interphase in the thermal expansion behavior of Al nanocomposite becomes more prominent with the reduction in the nanoparticle diameter. Also, the coefficient of thermal expansion of Al nanocomposite linearly decreases as SiC nanoparticle volume fraction increases.


2008 ◽  
Vol 59 ◽  
pp. 169-172 ◽  
Author(s):  
Thomas Schubert ◽  
T. Weißgärber ◽  
Bernd Kieback

The ideal thermal management material working as heat sink and heat spreader should have a high thermal conductivity combined with a reduced and tailorable thermal expansion. To meet these market demands copper composites reinforced with diamond particles were fabricated by a powder metallurgical method (powder mixing with subsequent pressure assisted consolidation). In order to design the interfacial behaviour between copper and the reinforcement different alloying elements, chromium or boron, were added to the copper matrix. The produced composites exhibit a thermal conductivity up to 700 W/mK combined with a coefficient of thermal expansion (CTE) of 7-8 x 10-6/K. The copper composites with good interfacial bonding show only small decrease in thermal conductivity and a relatively stable CTE after the thermal cycling test.


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