Composites of aluminum alloy and magnesium alloy with graphite showing low thermal expansion and high specific thermal conductivity

• Published in: Science and technology of advanced materials Vol. 18; no. 1; pp. 180 - 186
• Main Authors: Oddone, Valerio, Boerner, Benji, Reich, Stephanie
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 01.01.2017; Taylor & Francis Ltd; Taylor & Francis Group
• Subjects: 103 Composites; 104 Carbon and related materials; 201 Electronics / Semiconductor / TCOs; 210 Thermoelectronics / Thermal transport / insulators; 304 Powder processing / Sintering; 60 New topics / Others; Alloy powders; Alloys; Aluminum base alloys; Applications programs; Avionics; Composite materials; Graphite; Heat conductivity; Heat transfer; lightweight; Magnesium base alloys; Metal matrix composites; Mobile computing; New topics / Others; Oxidation; Plasma sintering; sintering; Spark plasma sintering; Tensile strength; Thermal conductivity; Thermal cycling; Thermal expansion; Thermal management; Thermal stress; Trace elements; 304 Powder processing / Sintering; sintering; 103 Composites; thermal expansion; 60 New topics / Others; 210 Thermoelectronics / Thermal transport / insulators; 201 Electronics / Semiconductor / TCOs; Metal matrix composites; 104 Carbon and related materials; graphite; thermal conductivity; lightweight
• ISSN: 1468-6996; 1878-5514
• DOI: 10.1080/14686996.2017.1286222

High thermal conductivity, low thermal expansion and low density are three important features in novel materials for high performance electronics, mobile applications and aerospace. Spark plasma sintering was used to produce light metal-graphite composites with an excellent combination of these three properties. By adding up to 50 vol.% of macroscopic graphite flakes, the thermal expansion coefficient of magnesium and aluminum alloys was tuned down to zero or negative values, while the specific thermal conductivity was over four times higher than in copper. No degradation of the samples was observed after thermal stress tests and thermal cycling. Tensile strength and hardness measurements proved sufficient mechanical stability for most thermal management applications. For the production of the alloys, both prealloyed powders and elemental mixtures were used; the addition of trace elements to cope with the oxidation of the powders was studied.