Fabrication of diamond particles reinforced Al-matrix composites by hot-press sintering

Abstract

Al-matrix composites reinforced by 50vol.% diamond particles under a 60MPa sintering pressure were fabricated by a vacuum hot-pressing method. The composite obtained a relative density of 96.5%. The coefficient of thermal expansion (CTE) and the thermal conductivity (TC) of the diamond/Al composites were measured by the laser flash method and differential dilatometry, respectively. Results showed that diamond/Al composites have high TC and low CTE with high sintering pressure (60MPa) and high volume fractions of diamond particles (50vol.%). The TC of the 50vol.% diamond/Al composite was 321W/mK, which is 112W/mK higher than that of pure Al (209W/mK). At temperatures ranging from 298K to 573K, the composite obtained low CTEs in the range of 13.2×10−6/K to 8.3×10−6/K, which satisfied the CTE of electronic packaging materials. The CTE values obtained in the experiment were approximately equal to the CTE calculated by the Kerner model [17]. The effects of volume fractions of diamond particles and sintering pressure on the density, TC, and CTE of diamond/Al composites were investigated.