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Development of new composite material based on Al matrix with low coefficient of thermal expansion

ФИО: Awais Qadir

Направление: Материаловедение

Научный руководитель: 1. Prof. Dr. Zolotorevskiy V.S. 2. Ass. Prof. PhD Pozdniakov A.V.

Институт: Институт экотехнологий и инжиниринга

Кафедра: Кафедра Металловедения цветных металлов

Академическая группа: MTM-14-1

Aluminum has a larger coefficient of thermal expansion (CTE) than those of ceramic substrates or semiconductor materials, resulting in thermal stresses that often cause components failure. Recently, high reinforcement content aluminum matrix composites receive much recognition in electronic packaging for their excellent, tailorable thermo-physical properties and low density. At the same time, as temperature cycling often exists in the operating environment of electronic components and a minor temperature variation would result in a length change within the composite, the thermal dimensional stability of packaging materials is of great importance for the reliability of electronic components. For most applications of Al-MMCs, CTE is a key parameter that needs to be carefully considered and tailored. Thereby, thermal expansion behavior of Al-MMCs has been extensively studied in the last decades. Previous studies primarily focused on materials reinforced with micrometer-sized particles, long fibers and whiskers; little attention has been paid to the materials with nanometer-sized reinforcing particles.

Al-5%Cu Metal Matrix with particulates B4C (2%, 5%, 7%) reinforced of size 0.5-20 µm produced via stir casting technique for the automotive applications. The mechanical properties were tested, microstructure were examined by Scanning Electron Microscopy (SEM) and analyzed CTE by dilatometer at 25 – 300°C. SEM results show that the distribution of B4C particles are uniformed in the composite and mechanical properties also increased with the content of B4C particles and suitable for automotive application. Results show that hardness increased with the amount of reinforcement B4C, the CTE was observed that CTE decrease with the increment of B4C. These results are satisfied for the piston applications.