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Li D.-G.,Harbin Institute of Technology | Chen G.-Q.,Harbin Institute of Technology | Jiang L.-T.,Harbin Institute of Technology | Lin X.,Heilongjiang Academy of Industrial Technology | Wu G.-H.,Harbin Institute of Technology
Acta Metallurgica Sinica (English Letters) | Year: 2015

In this work, aluminum alloy with a high concentration of magnesium (5A06) was reinforced with 55 vol% unidirectional ultra-high modulus and highly graphitized carbon fiber (M40J) using pressure infiltration method. The effect of temperature on the bending strength of the Cf/Al composites was investigated from room temperature to 500 °C. The experimental results showed that the strength of M40Jf/5A06Al composites was not affected by temperature from room temperature to 200 °C. The bending strength of the composite at 300 °C was decreased by 30% compared with that at room temperature. In order to evaluate the extent of interface weakening, the length of fiber pullout was measured. The results showed that the pullout length reached the maximum at 300 and 500 °C, which indicated weak interface at the corresponding temperature. The DSC curve presented obvious heat absorption peak at around 300 °C, which may be attributed to the dissolution of the interfacial product β (Al3Mg2) phases at the C/Al interface. The bending fracture surfaces of the composites after three-point bending tests were observed by SEM, plastic-viscous flow of the matrix were observed at the samples tested at 500 °C. The predominant mechanisms for high-temperature damage of M40Jf/5A06Al composites are matrix softening caused by dislocation recovery and interface weakening caused by the dissolution of interfacial products. © The Chinese Society for Metals and Springer-Verlag Berlin Heidelberg 2015.

Wang Y.,Harbin Institute of Technology | Jiang L.,Harbin Institute of Technology | Chen G.,Harbin Institute of Technology | Lin X.,Heilongjiang Academy of Industrial Technology | And 3 more authors.
Materials Characterization | Year: 2016

In the present work, carbon fiber reinforced magnesium-gadolinium composite was fabricated by pressure infiltration method. The phase composition, micro-morphology, and crystal structure of reaction products and precipitates at the interface of the composite were investigated. Scanning electron microscopy and energy dispersive spectroscopy analysis revealed the segregation of gadolinium element at the interface between carbon fiber and matrix alloy. It was shown that block-shaped Gd4C5, GdC2 and nano-sized Gd2O3 were formed at the interface during the fabrication process due to the interfacial reaction. Furthermore, magnesium-gadolinium precipitates including needle-like Mg5Gd (or Mg24Gd5) and thin plate-shaped long period stacking-ordered phase, were also observed at the interface and in the matrix near the interface. The interfacial microstructure and bonding mode were influenced by these interfacial products, which were beneficial for the improvement of the interfacial bonding strength. © 2015 Elsevier Inc. All rights reserved.

Wang P.,Harbin Institute of Technology | Xiu Z.,Harbin Institute of Technology | Jiang L.,Harbin Institute of Technology | Chen G.,Harbin Institute of Technology | And 2 more authors.
Materials and Design | Year: 2015

A practical and feasible approach is demonstrated to dramatically enhance thermal conductivity of the diamond particle reinforced aluminum matrix composites by means of optimized squeeze casting for fabricating metal-matrix composites with good adhesive interface as well as minimum thermal boundary resistance. By controlling the processing route, the architecture of diamond-aluminum interface was tuned, and therefore the thermal conductivity was amazingly found to be enhanced by 89% (from 321 to 606. W/(m·K)), which was the highest value reported in the scientific literature to date for diamond/aluminum composites using squeeze-casting method. Meanwhile, the bending strength was increased by 124% (from 98 to 220. MPa). This study offers an easily scalable and low-cost route to construct a wide range of particle reinforced metal matrix composites with significant enhancement of thermal performance. © 2015 Elsevier Ltd.

Chi H.,Harbin Institute of Technology | Jiang L.,Harbin Institute of Technology | Chen G.,Harbin Institute of Technology | Kang P.,Harbin Institute of Technology | And 2 more authors.
Materials and Design | Year: 2015

(TiB2+h-BN)/2024Al and TiB2/2024Al composites were fabricated by pressure infiltration technique. The dry sliding tribological behavior of the two composites was investigated using a pin-on-disk wear tester at the room temperature in atmospheric environment. With the addition of h-BN particles, the TiB2 particles were uniformly dispersed in the 2024Al matrix, however, TiB2 particles were observed to be partially agglomerated at some zones in TiB2/2024Al composites. The results of dry sliding tests showed that the addition of h-BN could improve tribological performance significantly especially at low sliding speed and low load, which was attributed to the role of h-BN on hindering the formation of compacted layer. Under different experimental conditions, three wear regimes could be distinguished considering the tribological properties and microstructural features. The wear mechanism map was established and the dominant wear mechanisms controlling these wear regimes were also discussed. © 2015 Elsevier Ltd.

Ma X.,Harbin Institute of Technology | Zhang Q.,Harbin Institute of Technology | Luo Z.,Harbin Institute of Technology | Lin X.,Heilongjiang Academy of Industrial Technology | Wu G.,Harbin Institute of Technology
Materials and Design | Year: 2016

A novel Ferro-Aluminum based sandwich composite for magnetic and electromagnetic interference shielding was designed and fabricated by hot pressing and subsequent diffusion treatment. The microstructure evolution of sandwich composite was characterized. Magnetic and electromagnetic interference shielding properties and mechanisms of the composites were also investigated. Sandwich composite is obtained with pure iron/Fe-Al alloy layer/pure iron structure and the Fe-Al/Fe interface shows good bonding. Al elemental content in reaction layer presents gradient distribution and the Al-riched brittle phase turns into ductile phase with diffusion time increasing. The electromagnetic shielding effectiveness of sandwich composite is higher than that of pure iron plate and increases with diffusion time extension, reaching 70 - 80 dB at the frequency of 30 KHz - 1.5. GHz. The multiple reflection loss in Fe-Al gradient layer is the primary contribution to the shielding effectiveness improvement of sandwich composite. The magnetic shielding effectiveness of sandwich composite can amount to 10. dB, about 2.5 times of that of pure iron plate. Fe-Al intermetallic layer, as non-magnetic spacer, is added between two iron plates and the permeable layer in sandwich composite can shunt magnetic field twice to improve shielding effectiveness. © 2015 Elsevier Ltd.

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