PSI - Issue 26

E. Solfiti et al. / Procedia Structural Integrity 26 (2020) 187–198 E. Solfiti and F. Berto / Structural Integrity Procedia 00 (2019) 000–000

196

10

microstructure, FG foils are good thermal interface materials. It was underlined by Gandhi and Pathak (2012) how the contact pressure can modify it depending strongly on the application: increasing the contact pressure leads to a minimization of the resistance, but overcoming such value can deform the surface and hence leading to an increment of that. A modeling proposal were done by Marotta et al. (2005) in order to describe such trend of the contact resistance against the contact resistance of FG foils with a percentage error of approximately 20%.

4. Summary

A short review of FG microstructure and related mechanical properties has been given in the first part and then the thermal conductivity and the strong relation with the electrical conductivity has been observed both against density and temperature. Their fundamental role on material modeling has been underlined. A large lack of data exists about the coe ffi cient of thermal expansion and specific heat capacity, especially their dependence on temperature. FG owns a collection of properties due to the graphitical nature, but all of them are often partially investigated or involve applications that do not require any further in-depth investigation. The heat transfer mechanism has not been well clarified and nor heating rate e ff ect is reported neither coupling of thermal e ff ect and mechanical loading. Modulus and strength changes are unknown at high temperature (a rough mention can be found in Dowell and Howard (1986) and thermal cycling e ff ect has never been reported. In an industrial world where the technological applications are looking for enhanced performances at very low weight and costs, the ease of production process, even in large volumes, make FG suitable for a more and more large variety of applications that could request an higher e ff ort of the background research. Asbury Carbons Inc., URL: https://asbury.com/materials/graphite/ . Bailey, A.C., Yates, B., 1970. Anisotropic thermal expansion of pyrolytic graphite at low temperatures. Journal of Applied Physics 41, 5088–5091. doi: 10.1063/1.1658609 . Balandin, A.A., 2011. Thermal properties of graphene and nanostructured carbon materials. Nature Materials 10, 569–581. doi: 10.1038/ nmat3064 . Bhattacharya, A., Hazra, A., Chatterjee, S., Sen, P., Laha, S., Basumallick, I., 2004. Expanded graphite as an electrode material for an alcohol fuel cell. Journal of Power Sources 136, 208–210. doi: 10.1016/j.jpowsour.2004.03.003 . Bonnissel, M., Luo, L., Tondeur, D., 2001. Compacted exfoliated natural graphite as heat conduction medium. Carbon 39, 2151–2161. doi: 10. 1016/S0008-6223(01)00032-X . Brooks, C.R., Bingham, R.E., 1968. The specific heat of aluminum from 330 to 890°K and contributions from the formation of vacancies and anharmonic e ff ects. Journal of Physics and Chemistry of Solids 29, 1553–1560. doi: 10.1016/0022-3697(68)90097-8 . Butland, A.T., Maddison, R.J., 1973. The specific heat of graphite: An evaluation of measurements. Journal of Nuclear Materials 49, 45–56. doi: 10.1016/0022-3115(73)90060-3 . Celzard, A., Mareˆche´, J.F., Furdin, G., 2005. Modelling of exfoliated graphite. volume 50. doi: 10.1016/j.pmatsci.2004.01.001 . Chaudhuri, S., Gravano, L., Marian, A., 2004. Optimizing top-k selection queries over multimedia repositories. volume 16. doi: 10.1109/TKDE. 2004.30 . Chen, P.H., Chung, D.D., 2012. Dynamic mechanical behavior of flexible graphite made from exfoliated graphite. Carbon 50, 283–289. URL: http://dx.doi.org/10.1016/j.carbon.2011.08.048 , doi: 10.1016/j.carbon.2011.08.048 . Chen, P.H., Chung, D.D., 2013. Viscoelastic behavior of the cell wall of exfoliated graphite. Carbon 61, 305–312. URL: http://dx.doi.org/ 10.1016/j.carbon.2013.05.009 , doi: 10.1016/j.carbon.2013.05.009 . Chen, P.H., Chung, D.D., 2014. Thermal and electrical conduction in the compaction direction of exfoliated graphite and their relation to the structure. Carbon 77, 538–550. URL: http://dx.doi.org/10.1016/j.carbon.2014.05.059 , doi: 10.1016/j.carbon.2014.05.059 . Chen, P.H., Chung, D.D., 2015. Elastomeric behavior of exfoliated graphite, as shown by instrumented indentation testing. Carbon 81, 505–513. URL: http://dx.doi.org/10.1016/j.carbon.2014.09.083 , doi: 10.1016/j.carbon.2014.09.083 . Chen, S., Moore, A.L., Cai, W., Suk, J.W., An, J., Mishra, C., Amos, C., Magnuson, C.W., Kang, J., Shi, L., Ruo ff , R.S., 2011a. Raman measure ments of thermal transport in suspended monolayer graphene of variable sizes in vacuum and gaseous environments. ACS Nano 5, 321–328. doi: 10.1021/nn102915x . Chen, S., Moore, A.L., Cai, W., Suk, J.W., An, J., Mishra, C., Amos, C., Magnuson, C.W., Kang, J., Shi, L., Ruo ff , R.S., 2011b. Raman measure ments of thermal transport in suspended monolayer graphene of variable sizes in vacuum and gaseous environments. ACS Nano 5, 321–328. doi: 10.1021/nn102915x . Chugh, R., Chung, D.D., 2002. Flexible graphite as a heating element. Carbon 40, 2285–2289. doi: 10.1016/S0008-6223(02)00141-0 . Chung, D.D., 1987. Exfoliation of graphite. Journal of Materials Science 22, 4190–4198. doi: 10.1007/BF01132008 . References