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

Al-matrix composites reinforced by 50 vol.% diamond particles under a 60 MPa 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 (60 MPa) and high volume fractions of diamond particles (50 vol.%). The TC of the 50 vol.% diamond/Al composite was 321 W/mK, which is 112 W/mK higher than that of pure Al (209 W/mK). At temperatures ranging from 298 K to 573 K, 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.

• Diamond particles reinforced Al-matrix composites were fabricated by vacuum hot-pressing method. • The effects of volume fractions of diamond particles and sintering pressure on the density, TC, and CTE of diamond/Al composites were investigated. • Diamond/Al composites have high TC and low CTE when sintering pressure is 60 MPa and volume fractions of diamond particles is 50 vol.%. • At temperatures ranging from 298 K to 573 K, the composite obtained low CTEs satisfied electronic packaging materials.