Papers by Author: Chang Rui Zhang

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Authors: Jia Cai Kuang, Da Xiang Yang, Jian Feng, Chang Rui Zhang
Authors: Yong Gang Jiang, Chang Rui Zhang, Feng Cao, Si Qing Wang, Bin Li
Abstract: Braided silica fibers reinforced nitride composite (SFRN), which was prepared by the polymeric precursor infiltration and pyrolysis (PIP) process with the precursor polyborosilazane (PSBZ), was a new typed microwave transparent material with high mechanical and ablation resistance performance for high-temperature application. The thermal ablation performance of the SFRN was evaluated by the ablation equipment with the kerosene and liquid oxygen as the heating source. The ablation surface texture of the SFRN including macrostructure and roughness were measured by Three-dimensional Macrostructure and Contour Scale System (TMCSS). Results showed that there are no concurrent observation of thermal delaminations or cracks and the specimen remains intact. The SFRN has an excellent thermal shock resistance and good ablation resistance with the linear recession rate of 0.038mm/s. The ablation surface texture of the SFRN can be well illuminated by the TMCSS. And the ablation performance will be improved by enhancing material density and homogeneous intertextures.
Authors: Xin Bo He, Xuan Hui Qu, Chang Rui Zhang, Xin Gui Zhou
Abstract: CF/SiC and Hi-Nicalon/SiC composites were prepared by precursor pyrolysis-hot pressing, and the microstructure and fracture behavior of the composites were investigated. Because of a strongly bonded fiber/matrix interface primarily resulting from the direct reactions between the fibers and matrix, Hi-Nicalon/SiC composite exhibited a typical brittle fracture behavior. However, CF/SiC composite displayed a tough fracture behavior with extensive fiber pullout, which was primarily attributed to a weakly bonded fiber/matrix interface as well as higher strength retention of the fibers. As a result, CF/SiC composite achieved better mechanical properties of 691.6 MPa in strength and 20.7 MPa•m1/2 in toughness, which were much higher than those of Hi-Nicalon/SiC composite.
Authors: Si’an Chen, Yu Di Zhang, Chang Rui Zhang, Xin Xiong, Hai Feng Hu
Abstract: The compression properties of C/SiC composite and Inconel X-750 helical springs were investigated from room temperature (RT) to 1000°C in air. The density of C/SiC spring is 1.74 g/cm3, only ~1/5 of X-750 value (8.17 g/cm3) and the spring constants of C/SiC and X-750 springs at RT are 3.47 and 5.61 N/mm, respectively. The spring constants of X-750 spring decreased with increase of temperature. X-750 spring could keep excellent property below 600°C, but its spring constant was only 36.7% of RT value at 800°C and permanent deformation appeared. At 1000°C, it could not restore and was destroyed. The spring constants of C/SiC spring at 400°C and 600°C were appreciably higher than the RT value, and then decreased with temperature elevating. Above 800°C, the spring constant decreased with test progressing because of the oxidation of carbon fibers and SiC matrix. But it has a spring constant of 2.40 N/mm (69.2% of the RT value) at 1000°C and can revert to its original dimensions.
Authors: Xin Gui Zhou, Chang Cheng Zhou, Chang Rui Zhang, Ying Bin Cao, Shi Qin Zou
Abstract: 3D braided carbon fiber reinforced silicon carbide (3D-Cf/SiC) composites were fabricated by precursor infiltration and pyrolysis(PIP), with carbon coatings prepared by chemical vapor deposition (CVD) before PIP. The effect of 1873K heat treatment on the mechanical properties of Cf/SiC composites were investigated. The results showed that heat treatment before PIP can increase the density of composites and lead to excellent properties of Cf/SiC composites. The flexual strength of the Cf/SiC composites with one cycle of 1873 K heat treatment reached 571 MPa, shear strength 51 MPa, and fracture toughness 18 MPa⋅m1/2.
Authors: Jun Sheng Li, Chang Rui Zhang, Bin Li, Feng Cao, Si Qing Wang
Abstract: Boron nitride coatings have been prepared by chemical vapor deposition using borazine as single precursor at 900 °C. The effect of the total pressure on the surface morphologies of the coatings was investigated. For low total pressures (≤ 3 kPa), the deposits presents a compact pebble-like surface structure. However, when high total pressures (> 3 kPa) were used, the surface of the coatings presents a loose grain-like feature. When the total pressure increases up to 12 kPa, the coatings shows a porous surface structure. The composition and structure of the deposited coatings were investigated by means of FTIR and XRD analysis. It shows that the coatings have a structure of turbostratic boron nitride.
Authors: Dan Zhao, Chang Rui Zhang, Hai Feng Hu, Yu Di Zhang, Qi Kun Wang, Xin Bo He
Abstract: Stitched carbon fiber cloth reinforced zirconium carbide composite (C/ZrC) was prepared by polymer infiltration and pyrolysis (PIP) process. C/ZrC-SiC composite was obtained by further introduction of SiC with PIP process in order to improve anti-oxidation property. The results show that 1.9vol% SiC addition improves the mechanical and anti-oxidation properties of C/ZrC composite. The flexural strength of C/ZrC is 247.9MPa, while that of C/ZrC-SiC is 273.1MPa. After oxidation in a muffle furnace at 1200°C for 30 minutes, the mass loss rate was reduced from 30.6% (C/ZrC) to 20.1% (C/ZrC-SiC), and the flexural strength and elastic modulus of C/ZrC were 56.7MPa and 5.7GPa, respectively, while those of C/ZrC-SiC were 122.9MPa and 17.2GPa, respectively.
Authors: Hong Liang Ji, Chang Rui Zhang, Xin Gui Zhou, Ying Bin Cao
Abstract: A new technology, prefabricating pore media (PPM) technology that adopt glass fiber as pore media, for porous transpiration cooling C/SiC composites was studied. The result shows that the technology can control the pore structure successfully by the volume content and distribution of glass fiber in the braid, and the porous C/SiC composites have good bending strength above 300MPa.
Authors: Feng Zhang, Hai Feng Hu, Qi Kun Wang, Yu Di Zhang, Chang Rui Zhang
Abstract: In this paper, 2D C/SiC composites with different carbon cloth filaments (1K, 3K) were prepared via precursor infiltration and pyrolysis (PIP) process. The flexural strength of 2D-1K C/SiC composites was 380MPa, and fracture toughness was 16.8MPa-m1/2, while those of 2D-3K C/SiC were 305MPa and 14.4MPa-m1/2, respectively. The differences of these two composites were analyzed from fiber volume ratio in the composites, density, and fracture surface (SEM) of the samples.
Authors: Si’an Chen, Hai Feng Hu, Yu Di Zhang, Chang Rui Zhang, Guang De Li
Abstract: Zirconium carbide (ZrC) coatings were prepared on C/C composite via molten salt reaction process at relatively low temperatures of 800-1000°C. During the reaction process, potassium fluorozirconate (K2ZrF6) played a role transporting zirconium from the molten salt to the C/C composite surface. Elevating reaction temperature increased the growth rate of coatings, simultaneously leaded to rougher coatings. The coatings growth rate increased with reaction time at first and then decreased gradually. The ZrC coatings prepared at 900°C for 5h was ~2m thickness. At the early stage, the low solubility of zirconium in the molten salt leaded to the low coatings growth rate. Secondly, the growth rate of the ZrC coatings was controlled by the chemical reaction between C/C composites and zirconium once zirconium was saturated in the molten salts. Thirdly, the control step of coatings formation turned into the diffusion of carbon through the formed ZrC coatings and which leaded to a gradual decrease of growth rate.
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