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Production and Properties of Copper Matrix Composite Containing Multi-walled Carbon Nanotubes
| Content Provider | Semantic Scholar |
|---|---|
| Author | Trinh, Phạm Văn Luận, Nguyễn Văn Minh, Phan Ngọc Phuong, Doan Dinh |
| Copyright Year | 2015 |
| Abstract | Multi-walled carbon nanotube (MWCNT)/copper composite powders with different CNT contents ranging from 0 to 2 wt.% were prepared by a high energy ball milling method has shown that CNTs are well dispersed in the matrix up to 1.5 wt.%. Dense specimens were prepared by vacuum sintering technique. The relative density and porosity were calculated from the measured and theoretical densities of the sintered specimens. The porosity increases by increasing CNT content due to the agglomeration of the CNTs in the copper matrix. Brinell hardness tests were performed to evaluate the hardness of CNT/Cu composites. The best CNT content enhancing the hardness of composite was determined as 1.5 wt.% CNT having hardness 35 percent higher than that of pure Cu at the same preparing conditions. The electrical resistivities of sintered specimens are measured with a four-probe method. The results show that the resistivity increases by increasing CNT content could be caused by the scattering during electron transfer at interface regions between CNTs and Cu particles. Kewords: carbon nanotubes, CNT/Cu composite, hardness, vacuum sintering INTRODUCTION Because of the combination of the outstanding properties of the metal matrix and reinforcement materials, metal matrix composites (MMCs) become one of the important materials mentioned recently due to their unique mechanical properties such as light weight and high elastic modulus, and their potential widely used in many industries such as aerospace, defense and security, mechanical, electrical, and electronics, etc [1-3]. Conventional MMCs reinforced with carbon fibers and particulates exhibit high specific strength and specific elastic modulus over their monolithic alloys. Recently, since the discovery of carbon nanotubes (CNTs) by Iijima [4], a number of investigations have been carried out to utilize this material as reinforcement in different materials, namely polymer, ceramics and metals, in order to combine the advantages of CNTs and metal matrix [5-8] due to its extraordinary properties such as very high mechanical properties, good electrical and thermal conductivity. Carbon nanotube reinforced metal matrix (MM-CNT) composites are prepared through a variety of processing techniques [9-13]. Powder metallurgy (PM) is the most popular and widely applied technique due to its combining easily different types of materials for yielding unique property combinations, for producing metal parts in a uniform and fine microstructure as well as preparing MM-CNT composites [7, 8, 14-17]. PM is a Pham Van Trinh, Nguyen Van Luan, Phan Ngoc Minh, Doan Dinh Phuong, Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay Distr., Hanoi, Vietnam Powder Metallurgy Progress, Vol.15 (2015), No 2 254 cost effective method that allows one to produce near net-shape parts and requires a low manufacturing temperature in comparison with the melting methods [16-19]. Some kind of materials had been produced successfully via the PM technique such as electrical contact materials [20, 21], copper alloys [22], and metal matrix composites [7, 8, 23]. Among MMC-CNTs, CNT/Cu composite is an important composite due to Cu and its alloys facile fabrication and generating a wide application oriented in electronics and electrical industries [24-27]. Reports on Cu/CNT composites deal with improvement in mechanical as well as electrical properties [28-30]. Researchers showed that the most critical issues in the processing of CNT-reinforced MMCs are (1) dispersion of CNTs and (2) interfacial bond strength between CNT and the matrix. Thus, ball milling of the initial powder mixture became a useful method for the production of composite powders by a solid-state reaction at room temperature [31, 32] with relatively inexpensive equipment, and ability to scale up production for commercial quantities [32]. Powder metallurgy technique, comprising compaction and sintering, helps increasing the hardness up to 20% with 15 vol. % CNT addition [33]. The improvement is not very great, but the processing route has the capability to be a very popular one, due to its ease if further improvement. The aims of this study are to fabricate and investigate some properties of CNT/Cu composite. High energy ball milling was applied for mixing and milling the mixture of CNT and Cu powder to obtain uniform dispersion of CNT within composite powders with CNT contents changing from 0 to 2 wt.% . Then the vacuum sintering method was utilized to produce the CNT/Cu composite specimens. These specimens were subjected to investigation of the dispersion of CNTs within Cu matrix, density, porosity, hardness as well as electrical resistivity. MATERIALS AND METHODS Materials To fix the initial condition for fabricating the CNT/Cu nanocomposite sample, copper powders of 27 μm in diameter purity 99.9 % produced by PEAXNM Co. were used as a matrix material shown in Fig.1 a). Multi-walled carbon nanotubes (MWCNTs) commercially produced by the Laboratory of Carbon Nanomaterials, Institute of Materials Science, VAST, with an average diameter of about 47 nm in diameter, 50 μm in length, and purity more than 95%, were used as the reinforcement component shown in Fig.1c). Tab.1. Milling parameters used for producing the composite powders Samples CNT content (wt.%) Ball/powder ratio (w/w) Rotation speed (rpm) Milling time (h) |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.imr.saske.sk/pmp/issue/2-2015/pmp_vol15_no2_p253-261.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
