Tomasz Boguszewski, Łukasz Ciupiński, Krzysztof Kurzydłowski, Warsaw University of Technology
Thermal properties of materials are becoming increasingly important in many applications. The reliability of e.g.
electronic components, that nowadays require high output power and high level of integration, strongly depends
on the heat management. The ideal thermal management material working as heat sink and heat spreader in
electronic packages should also have a CTE of 4-8 ppm/K. These requirements can be satisfied by metal matrix
composites (MMCs) that offer the possibility to tailor the properties of a metal by adding an appropriate
reinforcement phase. Diamond – copper composites are of special interest in this respect, however their thermal
performance is strongly dependent on the copper-diamond interface architecture and properties.
Finite element calculations were performed to model the influence of the interface to properties of the diamond
particle reinforced copper-matrix composite. Commercial code - Ansys and self-developed program were used in
the calculations. Heat flow was calculated in 2D and 3D model. Only conduction was considered, convection and
radiation were neglected.
Diamond particles with varying size were analysed and different volume fractions of diamond and the interfacial
phase were investigated.
The first results in 2D model show that composite with larger particles have better thermal conductivity but only if
the surface contribution is grater then 40%.
The models show also that the better the interface conductivity the better composite conductivity, however as the
relationship is asymptotic, so from the technical point of view there is no use to apply high conductivity interfaces.
The calculation are in agreement with analytical solutions.
In summary, these calculations could give the answer to the question what volume fraction of diamond particles
of a given size and properties and which interface properties and volume fractions should be sought for the design
of the copper-diamond composites for practical use.