Effects of initial density during laser machining assisted CVI process and its influence on strength of C/SiC composites

Wang, Jing; Zhang, Yunhai; Liu, Yongsheng; Cao, Liyang; Chen, Jie

doi:10.1016/j.ceramint.2020.01.207

Cited by 19 publications

(15 citation statements)

References 23 publications

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“…Therefore, more methyltrichlorosilane (MTS) precursor could easily diffuse into the preform during CVI process, leading to the increased final density. 2,3 However, the final density of the as-obtained MPCF-C/SiC here displayed a different behavior from that of Wang et al reported, 3 which even increased with the initial density.…”

Section: Density Porosity and Microstructurecontrasting

confidence: 65%

“…As CVI cycle increased, the diffusion of MTS gases into the inner preform became progressively challenging. 3 Thus, lots of reopened pores near the MPCF were blocked by SiC matrix, as shown in parts circled with white box in Figure 2. However, for MPCF-ID-191, the size of closed pores was mainly distributed from 50 to 150 μm.…”

Section: Density Porosity and Microstructurementioning

confidence: 99%

“…The pores in preform decreased in size after several CVI cycles, according to previous investigations. 3,20 Nonetheless, the use of laser machining to prepare micro-holes induced some differences. The closed pores can be reopened by the laser machining to accept more MTS gases to diffuse into, thereby decreasing the porosity and pore size of the composites ( Figure 4B).…”

Section: Density Porosity and Microstructurementioning

confidence: 99%

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Effect of initial density on thermal conductivity of new micro‐pipeline heat conduction C/SiC composites

et al. 2020

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Two-dimensional C/SiC composites have attracted increasing interests in recent years due to their low densities, high specific strengths, 1 elevated specific module, 2 and noncatastrophic mode of failure, 3 which made them promising thermal structural materials for applications in aerospace, aircraft braking, and space detection. 1,4,5 However, these harsh environments require them possessing not only thermal structural performances like load resistance, 2 but also functional properties such as high thermal conductivity, especially in thickness direction of the composites (about 5-12 W•m −1 •K −1 for now). 6-9 Therefore, C/SiC composites cannot serve as a functional materials for aerospace vehicle thermal discharge

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Section: Density Porosity and Microstructurecontrasting

confidence: 65%

Section: Density Porosity and Microstructurementioning

confidence: 99%

Section: Density Porosity and Microstructurementioning

confidence: 99%

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Effect of initial density on thermal conductivity of new micro‐pipeline heat conduction C/SiC composites

et al. 2020

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“…where σ(t) is the pressure at the entrance of the channel (related to the time accumulation) and J c represents the destructive threshold of the material. Table. 2 showed the parameters used in our previous works [26][27][28]30]. Based on the above research analyses, 8000 mW laser power was employed as an optimal value to produce different arrangements of mass transfer channels.…”

Section: Effect Of Femtosecond Laser Power On Quality Of Mass Transfementioning

confidence: 99%

“…Compared to other machining technologies, LA-CVI method can be de ned as a middle-stage machining technology with reduced irreversible damage, as well as enhanced densi cation and mechanical properties due to the formation of "dense band". We have successfully studied the effects of parameters of LA-CVI to determine the optimal values, such as the initial density [27] of C/SiC composites and diameter [28] of mass transfer channels. However, further analysis of the relationship between femtosecond laser processing parameters and the quality of mass transfer channels is required to gain a better understanding of the method.…”

Section: Introductionmentioning

confidence: 99%

Effect of mass transfer channels on flexural strength of C/SiC composites fabricated by femtosecond laser assisted CVI method with optimized laser power

Wang

Cao

Zhang

et al. 2020

Preprint

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In this work, femtosecond laser assisted-chemical vapor infiltration (LA-CVI) was employed to produce C/SiC composites with 1, 3, and 5 rows of mass transfer channels. The effects of laser machining power on the quality of produced holes were investigated. The results showed that the increase in power yielded complete hole structures. The as-obtained C/SiC composites with different mass transfer channels displayed higher densification degrees with flexural strengths reaching 546±15 MPa for row mass transfer channel of 3. The strengthening mechanism of the composites was linked to the increase in densification and formation of “dense band” during LA-CVI process. Multiphysics finite element simulations of the dense band and density gradient of LA-CVI C/SiC composites revealed C/SiC composites with improved densification and lower porosity due to the formation of “dense band” during LA-CVI process. In sum, LA-CVI method looks promising for future preparation of ceramic matrix composites with high densities.

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Microstructure and Ablation Behavior of W/ZrC/SiC Coating on C/C Composites Prepared by Reactive Melt Infiltration and Atmospheric Plasma Spraying

Zhou

Niu

et al. 2021

Adv Eng Mater

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A W/ZrC/SiC multilayer coating is prepared on carbon/carbon (C/C) composites by reactive melt infiltration (RMI) and atmospheric plasma spray (APS). The morphology and microstructure of the coating are characterized by scanning electron microscopy coupled with energy dispersive spectrometry (SEM‐EDS), X‐ray diffraction (XRD), and focused ion beam (FIB) and transmission electron microscopy (TEM). Microstructure analysis reveals that the gradient coatings exhibit smooth surface morphology, well‐defined interfaces, uniform thickness, and a highly dense architecture. After 60 s of ablation, the linear ablation rates (LARs) and mass ablation rates (MARs) of the coated composites stand at 2.58 × 10−3 mm s−1 and 5.25 × 10−3 g s−1, respectively. In general, the reason for the great ablation resistance of W/ZrC/SiC‐coated C/C composites is the comprehensive effect of the multilayer coating. The outer W coating is used as the first barrier layer to resist most thermal shocks. Then, the molten eutectics SiO2–ZrO2 formed in the ZrC/SiC layer at service temperature can fill the pores and act as a second diffusion barrier for oxygen and heat.

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Effects of initial density during laser machining assisted CVI process and its influence on strength of C/SiC composites

Cited by 19 publications

References 23 publications

Effect of initial density on thermal conductivity of new micro‐pipeline heat conduction C/SiC composites

Effect of initial density on thermal conductivity of new micro‐pipeline heat conduction C/SiC composites

Effect of mass transfer channels on flexural strength of C/SiC composites fabricated by femtosecond laser assisted CVI method with optimized laser power

Microstructure and Ablation Behavior of W/ZrC/SiC Coating on C/C Composites Prepared by Reactive Melt Infiltration and Atmospheric Plasma Spraying

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