SONG Gui-ming, WU Ying. Processing and Elevated Temperature Strength of TiC Composites Reinforced with Carbon Fibers[J]. Journal of Materials Engineering, 2001, 0(9): 3-6,17.
TiC-20vol% carbon fiber composites were prepared using hot-pressing, and the effect of sintering temperature and fiber on the mechanical properties of the composites were investigated The discontinuous carbon fibers were uniformly distributed in TiC matrix using wet ball-milling mixing The suitable hot-pressing temperature for Cf/TiC composites was 2100℃. The strength values of Cf/TiC composites at room temperature and 1400℃ were 593MPa and 439MPa, respectively, and the fracture toughness value was 6.87MPa·m1/2. The strengthening and toughening effects of carbon fibers were evaluated.
LI Wan-feng, YANG Yuan-sheng, YU Li, ZHANG Yun, HU Zhuang-qi. Effect of Direct Current Electric Field on the Microstructure of Nickel-based Superalloy K417G[J]. Journal of Materials Engineering, 2001, 0(9): 7-9,13.
The effect of a DC electric field on the solidified microstructure of nickel-based superalloy K417G is studied. The experiment results show that the electric field causes the changes of the morphologies of dendrites and carbides, and the changes of the preferred orientation, morphology, and distribution of the precipitated gamma prime phase. The mechanism of the mentioned results produced by the electric field is discussed.
QIU Gui-xue, WU Ren-jie. Predicting Creep Behavior of Elastomer Modified Polypropylene by Using Dynamical Testing Procedures[J]. Journal of Materials Engineering, 2001, 0(9): 10-13.
Creep of elastomer modified PP under static load can be predicted from dynamical testing (Fatigue). A variation of the amplitude near a constant mean load allows extrapolation to static load conditions. Good agreement is achieved between the calculation from dynamic testing and static creep behavior. This technique will effectively reduce the testing duration.
WANG Ji-gang, GUO Quan-gui, LIU Lang, SONG Jin-ren. Research on Adhesion between the Adhesives Consisting of Phenol-Formaldehyde Resin Mixed with White Carbon Black and B4C Powders and Graphite at High Temperatures[J]. Journal of Materials Engineering, 2001, 0(9): 14-17.
White carbon black particles were introduced into the formal adhesive consisting of phenol-formaldehyde resin mixed with B4C powders to prepare a novel high temperature adhesive. Graphite materials were bonded with the adhesive and their shear strength after heat-treatment at different temperatures were tested subsequently. It was indicated that the novel adhesives possessed excellent heat-resistivity and good adhesion to graphite with the temperature up to 2550℃. Photography of fractured sections of the bonded samples were observed by SEM. The relationship between the composition, structure of the adhesives and the adhesive shear strength of the bonded samples was analyzed. Results demonstrated that white carbon black′s introduction was helpful to improve the density and adhesion at the interface of the bonded samples.
SUN Yong-xing, WANG Yin-zhen, HE Yan-ling. Influence of Additive on the Microstructure and the Resistance to Corrosion of Plasma Sprayed Cr2O3 Coating[J]. Journal of Materials Engineering, 2001, 0(9): 18-20,24.
The influence of additive CeO2 and SiO2 with different content on the microstructure and the resistance to corrosion of plasma sprayed Cr2O3 coating was studied. It is found that adding just the right amount of CeO2 and SiO2 to Cr2O3 layer reduces the-amount and the size of the pores in layer, and thus increases resistance to corrosion.
LI Ai-min, SUN Kang-ning, ZHANG Yu-jun, LI Jing, YIN Yan-sheng. The Influence of Cr on the Toughness of Fe-Al/Al2O3 Composites[J]. Journal of Materials Engineering, 2001, 0(9): 21-24.
Fe-Al/Al2O3 composites were prepared by the method of mechanical alloying and hot-pressing sintering. The sample was tested by the methods of X-ray diffraction, spectrum, and TEM. We found that the fracture toughness of the composites was increased sharply, and the highest number exceeded 15.00MPa·m1/2. At the same time, the rod crystal and "N" type structure were advantageous to the toughness of the composites.
YIN Xiao-wei, CHENG Lai-fei, ZHANG Li-tong, XU Yong-dong. Oxidation Resistance of 3D C/SiC Composites Protected with Cr-Si Alloy Coating[J]. Journal of Materials Engineering, 2001, 0(9): 25-27,30.
The microstructure and oxidation resistance of 3D C/SiC composites protected with SiC/Cr-Si coating were investigated in dry air from 400 to 1500℃ for 10 hours, which was compared with SiC-coated C/SiC composites. The former showed better oxidation resistance than the latter during 1000～1500℃, which resulted from the filling of the defects in SiC coating by Cr-Si coating. However, C/SiC composite with SiC/Cr-Si coating showed worse oxidation resistance during 500～700℃, which resulted from the bigger CTE mismatch between the coating and matrix.
LUO Rui-ying. Research of New Technology of Regenerating Carbon/Carbon Composites[J]. Journal of Materials Engineering, 2001, 0(9): 28-30.
The new technology of regenerating C/C composites used for aeroplane brake was developed C/C composite aeroplane brake discs was reclaimed by high temperature binding method. Interlamination shear strength (ILSS) of C/C composites regenerated is 6-99 MPa, and it is higher than that of C/C composites used to wear service life (5-22MPa). The analyses of SEM showed that-the binding surface of test specimen was not delaminated in shear test. The coating of protection regenerated C/C composites from oxidation possesses better oxidation-resistant properties. The inertia dynamic test confirmed that carbon discs meets the needs of aeroplane brake.
SUN Lan, PAN Jin-sheng. Mechanical Properties of TiC Particles Reinforced MoSi2 Composites[J]. Journal of Materials Engineering, 2001, 0(9): 31-34.
TiCp-MoSi2 composites with different volume percent were fabricated by wet mixing and hot pressing processing. The effects of TiC particles on microstructure and mechanical properties of MoSi2 matrix were investigated. The results indicated that the grain size of MoSi2 matrix material decreased and its mechanical properties were improved because of the addition of TiC particles The composites displayed an increase of 65% in bending strength for 40vol%TiCp additive and an improvement of 53% in fracture toughness for 20vol%TiCp additive over the values of the matrix. The load-bearing capability of MoSi2 at elevated temperature was increased rapidly due to the addition of TiC particles and the flexural strength of composite increased with increasing the content of TiC particles.
LI Yan, LI Di, ZHANG Ji. The Influences of Microalloying of Ni and B on Work Hardening and Flow Softening of TiAl During Hot Deformation[J]. Journal of Materials Engineering, 2001, 0(9): 35-38.
Isothermal compressive tests were conducted at 1000℃/0.1s-1 in order to reveal the effects of microalloying of Ni and B on work hardening and flow softening of TiAl. It was found that Ni addition stabilizes the work hardening rate, decreases the softening degree and rate. The B addition accelerates the attenuation of work hardening rate, increase the softening degree and produce surged softening rate Comparatively, Ni addition is the key factor to improve the steady-state flow behavior of TiAl.
JIANG Li-xiang, HE Shi-yu, YANG Shi-qin, CHEN Ping, SHENG Lei. Application of Carbon(grphite) Fiber/Epoxy Composites in the Spacecraft and the Research on Their Behaviors[J]. Journal of Materials Engineering, 2001, 0(9): 39-43,46.
Characters and effects of the space environment factors including solar electromagnetic radiation, charged particles radiation, vacuum circumstance, cold-dark condition, erosion of atomic oxygen, micro-meteor and impact of space fragment were introduced. Properties of carbon (graphite) fiber/epoxy matrix composites were summarized. Application and research of design and manufacture for spacecraft of these materials were reviewed.
ZHANG Shou-yang, LI He-jun, SUN jun. An Investigation on the Densification Efficiency of LTCVI[J]. Journal of Materials Engineering, 2001, 0(9): 44-46.
On the basis of isothermal CVI and thermal gradient CVI, Forced Flow-Thermal Gradient CVI(FCVI), with the main advantage of rapid densification, was brought forth. In this dissertation, a systematic study on FCVI for the fabrication of carbon/carbon composites has been made via theoretical analysis and experiments. Moreover, an advanced CVI process-Limited thermal gradient CVI(LTCVI) was put forward. In this paper, based on the analysis of preform structure, the evaluating method for densification efficiency of LTCVI was introduced and was investigated, moreover, a principle was concluded to improve the efficiency of LTCVI, this principle also can be applied in other CVI process.
