EFFECT OF ULTRASONIC-ASSISTED COMPACTION ON DENSITY AND HARDNESS OF Cu-CNT NANOCOMPOSITES SINTERED BY CAPSULE-FREE HOT ISOSTATIC PRESSING

Abstract

Cu-CNTs composites were prepared with and without ultrasonic-assisted compaction in this work. The samples were sintered by capsule-free hot isostatic pressing at 920 o C and 50 MPa Ar gases. The results showed that the higher relative density and Brinell hardness were obtained for ultrasonic assisted compaction samples (at the same CNT content). For both cases, the highest hardness values was achieved at 0.5 wt.% CNT (49.2 HB and 45.8 HB for specimens with and without the ultrasonic-assisted compaction, respectively). The hardness was then decreased as the CNT content increased. The higher hardness values were resulted from higher densification of the sintered samples with ultrasonic-assisted compaction compared to the others.Keywords: Cu-CNT composites, carbon nanotubes, ultrasonic, compaction, hot isostatic pressing 1 Introduction Due to the unique properties of carbon nanotubes (CNT) such as high strength, good thermal conductivity and electrical properties, it's considered to be an ideal reinforcement for metal matrix composites [1][2][3]. An increasing of researches concerning with CNTs reinforced metal matrix composites (CNT-MMC) has been carried out in recent years. There are several techniques to fabricate CNT-MMC including powder metallurgy, electrodeposition, electroplating, melting and spray coating methods [3][4][5][6][7][8][9]. In which, powder route is the most popular method being used. The basic steps of the method include mixing CNT with metal powder (Al, Cu, Ni, etc.) via a mechanical alloying, and following by compaction and sintering. Up to date, the challenge is how to induce a uniform dispersion of CNT in metal matrix, especially, for high CNT amount. The strong van der Waal's force of attraction among CNT, the density discrepancy between CNT and metal matrix, the tendency to agglomeration and tangle together of CNT are attributed to the poor dispersion of CNT in the metal matrix. Besides that the weak interface bonding between CNT and metal matrices due to the poor wettability characteristic of CNT with metal matrices also restrict the incorporation of CNT with metal matrix. And so, these cause the reduction in their expected properties of the composites. Several methods have been proposed to improve the homogeneity

Evaluation of the Material Properties of the Ti and CoCr Alloys Prepared by Laser Powder Bed Fusion

“…Powder Metallurgy (PM) engineering starts to use a new possibility of design controlled by the new technologies, led by additive manufacturing (AM), ultrasonic-assisted compaction or/and sintering, severe plastic deformation (SPD) and it has a huge potential to disrupt current manufacturing process processing. Mainly AM is to take care of a forum demonstrating the depth and breadth of the research and development activities through manufacturing technology which most describes that goal [1][2][3][4].…”