Papers by Keyword: Cu Matrix Composites

Abstract: In this work, a new type of B₁₃P₂ reinforced Cu matrix composite (B₁₃P₂/Cu) with excellent wear resistance properties has been fabricated. The experimental results reveal that when the total content of P and B was 3wt.% and the mass ratio of P to B was 2:3, the brittle reticular divorced eutectic Cu₃P disappeared and B₁₃P₂ phase uniformly distributed in Cu matrix. The microstructure can be controlled and designed according to the ratio of P and B. The microhardness of B₁₃P₂ reached up to 1837 HV, which was as high as that of SiC, while the mircohardness of Cu matrix was about 5 times more than pure that of Cu. The wear resistance data indicate that the largest weight loss of pure Cu was approximately four times more than that of the B₁₃P₂ reinforced composites at the 40 min. The CTE of the new composites also decreased as compared with pure Cu.

Abstract: Cu matrix composites with various contents of Ti₂AlN were fabricated by powder metallurgy using spark plasma sintering (SPS) method. Ti₂AlN ceramic particles were pre-treated by electroless copper plating, the result showed that Ti₂AlN reinforcement and Cu matrix were strongly bonded. The effects of Ti₂AlN content on microstructure, electrical resistivity and mechanical properties were systematically investigated. With the addition of low fraction of Ti₂AlN, the hardness and tensile strength of matrix were improved without losing the fracture toughness too much. Tensile strength of Ti₂AlN/Cu composites were about 380 MPa with the content of 7 wt. % reinforcing phase, and the conductivity of the composites remained about 61.5 % IACS. Moreover, the wear tests illustrated that the loads were effectively born by the Ti₂AlN reinforcement, the main tribological mechanism changed from adhesive wear to abrasive wear compared with Cu, thus the friction and wear resistance was also obviously improved.

Abstract: TiB₂ is a superhard, high-temperature and high corrosion resistant material and it is under consideration for tungsten-free cutting tools and high temperature structural applications. Although such a covalent compound requires significantly elevated temperature for the consolidation, great exothermicity of TiB₂ synthesis by means of SHS (Self-propagating High-temperature Synthesis) can be “ïn situ” utilized. In this study, TiB₂-based composites are fabricated from titanium, boron and binder metal. In order to optimize consolidation process and improve fracture toughness of the products, three types of binder, based on cobalt, nickel or copper were investigated. In respect to hardness, limited amount of binder, 5, 10 or 15 vol.% respectively, were applied; each time 5 vol.% of Ti addition for reaction with boron completeness was used. The TiB₂ based composites were fabricated from elements in one process by means of the SHS process combined with p-HIP (pseudo-hot isostatic pressing) method. The raw elemental powders were homogenized by wet mixing using ball milling technique. Dried mixtures were pressed into a compact, coiled by heating element and then exposed to the SHS-p-HIP process. After SHS initiation, the compact was pressed pseudo-isostatically under pressure of 190MPa for 5 min. The sintering additives and their concentrations significantly affected the consolidation process as well as the properties of composites. The highest hardness was obtained for samples sintered with cobalt, containing intermetallic binder. However, elemental metal binder was detected as a main component for samples sintered with copper. The relative density, SEM microstructure, phase composition and hardness are compared in this study.

Abstract: A SiC_p/Cu composite with excellent performance is prepared by using the advanced powder injection molding technology. The microhardness and tensile strength of the composite are detected, and the surface microstructure and the tensile fractures are observed. The results show that SiC particles are uniformly distributed in Cu matrix and excellently bonded with the Cu matrix. With the increase of the SiC content, the microhardness of the composite is increased while the tensile strength is increased first and then decreased. A crackle source of the composite for tensile fracture mainly includes two kinds: cracking of the Cu matrix in vicinity of the SiC particles and debonding of an interface of the SiC particles and the Cu matrix.

Abstract: The nano-SiC whisker reinforced Cu-matrix composites (SiCw/Cu) were obtained by powder metallurgy processes. The electrical arc ablation performance of composite SiCw/Cu was compared with copper H62 through stagnation-point ablation experiments. The results indicated that the qualities of copper H62 samples decreased with the increasing of ablating current; and the qualities of SiCw/Cu samples firstly increased and then decreased with the increasing of ablating current. Ablation mechanism research indicates the ablation hole of SiCw/Cu is smaller than copper H62, but it produced micro cracks because of different thermal expansion coefficients between nano-SiC whisker and Cu-matrix. At the same time, nano-SiC whisker happens to intricate oxidation reaction during arc ablation, it can reduce Cu-matrix smelts and sprays by absorbing arc energy. The anchoring effect and protection for the copper matrix of the uniformly dispersing nano-SiC whiskers have been considered to contribute the excellent arc ablation performance of composite SiCw/Cu.

Abstract: The microstructure and wear behavior of Cu-TiC composite which prepared by spark plasma sintering (SPS) and mechanical alloying (MA) were discussed in this paper. X-ray diffraction patterns and scanning electronic microscopy (SEM) images indicate that TiC were formed during sintering process. The pin-on-disc wear test was carried. Confocal scanning laser microscope (CFSLM) images indicate that mechanical mixed layer appeared on the worn surface the mechanical mixed layer broken up when normal load reached 200N. The composites displayed excellent wear resistance with 2.38×10−5 mm3/Nm specific wear loss.

Abstract: SiC particle reinforced Cu composite was fabricated by powder metallurgy and hot extrusion process. The friction behaviour of pure Cu, braze and composites was studied on a block-on-ring test. The blocks were slid against 40Cr steel rings under the lubrication of 232# machinery oil. It shows that the wear rate of pure Cu is about then times of the 5 vol.% Cu composite at a normal load of 300 N. The satisfied wear resistance prove the SiC is a promising reinforcement material for Cu matrix composite. However, the 20 vol.% SiC did not exhibit prospected wear resistance. The discussion of this phenomenon was conducted.