Kun LI
,
Nanlin SHI
,
Jun GONG
,
Chao SUN
,
null
,
null
,
null
,
null
材料科学技术（英）
Four kinds of Mg alloys reinforced with carbon fibres were fabricated by a gas pressure infiltration technique. The fibres were pre-coated a SiO2 layer prior to fabrication. Different microstructures and interactions in the fibre-matrix interface of these composites were observed by transmission electron microscopy (TEM). The results showed that the interfacial interaction strongly depended on the content of Al in the Mg-based matrices. The microstructure of the interface could then be controlled by adjusting the Al content of the Mg-based matrix. In addition, fibres extracted from different Mg-based matrix all had some degradation owing to the interfacial reaction and the fibre-matrix interdiffusion.
关键词:
Carbon fibre
,
null
,
null
,
null
Yongrui LI
,
Nanlin SHI
材料科学技术（英）
Ultrafine Fe3O4 powder was successfully synthesized via a novel ageing process from a precursor FeO(OH), which was the hydrolysate of FeCl3 in the urea solution. The structure of as-synthesized powder was characterized by X-ray diffraction (XRD), and the morphology of these nanoparticles was investigated using a transmission electron microscope (TEM). Pure phase Fe3O4 was obtained and the mean diameter of these nanoparticles was about 21nm. Furthermore, the study indicated that the precursor FeO(OH) played an important role in the formation of Fe3O4 nanoparticles. The mechanism was also discussed.
关键词:
Powder technology
,
null
,
null
,
null
Yanhua LI
,
Nanlin SHI
,
Dezhi ZHANG
,
Rui YANG
材料科学技术（英）
A continuous loading push-out test technique was used to measure the interfacial shear strength of SiC fiber reinforced Ti matrix composites. The interfacial shear strength of samples as-fabricated and after heat exposed at 700 and 800℃ for 50 h was successfully determined. It has been found that the interfacial shear strength of the specimen exposed at 700℃ was higher than that of as-prepared and exposed samples at 800℃. The shear strength of the as-prepared samples was about 112.45 MPa, and increased to about 153.77 MPa after heat-treating at 700℃ for 50 h, but decreased to 133.11 MPa after treating at 800℃ for 50 h. Scanning electron microscope (SEM) was used to investigate the interfacial morphology of the samples. The brittle phase was the main products of interface for samples exposed at 800℃, and the interface was easily peeled off.
关键词:
Push-out test
,
null
,
null
,
null
Guoxing ZHANG
,
Qiang KANG
,
Nanlin SHI
,
Geping LI
,
Dong LI
材料科学技术（英）
In order to evaluate the interfacial reaction, a SiCf/Ti (TA1) composite was fabricated by a vacuum hot pressing method and then heat-treated in vacuum at 800℃ for up to 100 h. The elemental distributions of C, Si and Ti at the interfacial reaction zone were investigated. It was found that the reaction zone occurs during the fabrication process and continuously grows at high temperature because the Si and C atoms diffuse from SiC fibers to the matrix and Ti atoms diffuse in the opposite direction. The growth of the reaction zone is diffusion controlled and the mechanism of the reaction can be described by a reactive diffusion model of solid-state growth of an AmBn layer between two elementary substances A and B.
关键词:
SiCf/Ti (TA1) composite
,
null
,
null
Xuemei GUO
,
Kun LUO
,
Nanlin SHI
材料科学技术（英）
In the presence of p-toluene sulfonic acid (TSA) as a dopant, polyaniline (PAni) nanofibers, (about 80~165 nm in diameter) were successfully synthesized with a chemical template-free method. It was found that the formation probability, morphology, and diameter of the resulting PAni-TSA nanofibers were sensitive to the synthetic conditions, such as reaction temperature, the molar ratio of TSA to aniline, and the concentration of TSA in the polymerization media. The molecular structure was characterized by using the FT-IR, Raman spectra and X-ray diffraction, which shows that the main chain structure of PAni-TSA nanofibers was in agreement with that of granular PAni.
关键词:
Polyaniline
,
null
,
null
,
null
