Effects of Interphase Thickness on Damping Behavior of 2D C/SiC Composites

2007 ◽  
Vol 546-549 ◽  
pp. 1531-1534 ◽  
Author(s):  
Qing Zhang ◽  
Lai Fei Cheng ◽  
Wei Wang ◽  
Xi Wei ◽  
Li Tong Zhang ◽  
...  
Keyword(s):  
Internal Friction ◽  
Chemical Vapor ◽  
Mechanical Analysis ◽  
Chemical Vapor Infiltration ◽  
Damping Capacity ◽  
Air Atmosphere ◽  
Damping Behavior ◽  
Sic Composites ◽  
Lower Temperature ◽  
Damping Peak

Internal friction of 2D C/SiC composites fabricated by chemical vapor infiltration (CVI) method was measured by dynamical mechanical analysis (DMA) at different frequencies from room temperature (RT) to 400°C in air atmosphere. Internal friction of 2D C/SiC composites increased gradually with increasing temperature and then decreased after damping peak appeared in the temperature range of 250°C to 300°C. Damping capacity and peak value decreased gradually with increasing frequency, accompanied with a shift of damping peak towards lower temperatures. Moreover, the effect of interphase thickness on damping behavior of 2D C/SiC composites was investigated. The results showed that damping peak of the composites increased gradually and the temperature of the peak shifted to the lower temperature with increasing PyC interphase thickness, when the interphase thickness is in the range of 90~296nm. The influence of interphase thickness on interfacial bonding strength, sliding resistance and the microstructure of SiC matrix was discussed, which was considered to be responsible for the results.

Microstructures, Strength and Toughness of 2D Cf/(C-SiC) Composites by Chemical Vapor Infiltration

2009 ◽  
Vol 24 (5) ◽  
pp. 939-942 ◽  
Author(s):  
Zhi-Xin MENG ◽  
Lai-Fei CHENG ◽  
Li-Tong ZHANG ◽  
Yong-Dong XU ◽  
Xiu-Feng HAN
Keyword(s):  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Sic Composites ◽  
Strength And Toughness ◽  
Vapor Infiltration

Effects of Macroscopic Pores on the Damping Behaviors of Metal Materials

2011 ◽  
Vol 66-68 ◽  
pp. 1155-1162
Author(s):  
Jian Ning Wei ◽  
Gen Mei Li ◽  
Li Ling Zhou ◽  
Xue Yun Zhou ◽  
Jian Min Yu ◽  
...  
Keyword(s):  
Internal Friction ◽  
Pure Aluminum ◽  
Air Pressure ◽  
Damping Capacity ◽  
Infiltration Process ◽  
Pressure Infiltration ◽  
Temperature Range ◽  
Commercially Pure ◽  
Damping Behavior ◽  
Metal Materials

A large number of macroscopic pores were introduced into commercially pure aluminum (Al) and Zn-Al eutectoid alloy by air pressure infiltration process to comparatively study the influence of macroscopic pores on the damping behaviors of the materials. Macroscopic pores size are on the order of a millimetre (0.5~1.4mm) and in large proportions, typically high 76vol.%. The damping behavior of the materials is characterized by internal friction (IF). The IF was measured on a multifunction internal friction apparatus (MFIFA) at frequencies of 0.5, 1.0 and 3.0 Hz over the temperature range of 25 to 400 °C, while continuously changing temperature. The damping capacity of the metal materials is shown to increase with introducing macroscopic pores. Finally, the operative damping mechanisms in the metal materials with macroscopic pores were discussed in light of IF measurements.

Ring compression properties of SiCf/SiC composites prepared by chemical vapor infiltration

2018 ◽  
Vol 44 (18) ◽  
pp. 22529-22537
Author(s):  
Yue Li ◽  
Zhaoke Chen ◽  
Ruiqian Zhang ◽  
Zongbei He ◽  
Haoran Wang ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Compression Properties ◽  
Ring Compression ◽  
Sic Composites ◽  
Vapor Infiltration

High toughness, 3D textile, SiC/SiC composites by chemical vapor infiltration

2001 ◽  
Vol 318 (1-2) ◽  
pp. 183-188 ◽  
Author(s):  
Yongdong Xu ◽  
Laifei Cheng ◽  
Litong Zhang ◽  
Hongfeng Yin ◽  
Xiaowei Yin
Keyword(s):  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
High Toughness ◽  
Sic Composites ◽  
Vapor Infiltration

The Stability of BN Interfacial Coatings in CFCC Systems During Oxidation and Exposure to Moisture

1997 ◽  
Vol 3 (S2) ◽  
pp. 729-730
Author(s):  
K.S. Ailey ◽  
K.L. More ◽  
R.A. Lowden
Keyword(s):  
Elevated Temperatures ◽  
Impurity Content ◽  
Chemical Vapor ◽  
Ceramic Matrix Composites ◽  
Chemical Vapor Infiltration ◽  
Forced Flow ◽  
Crystallographic Structure ◽  
Matrix Composites ◽  
Sic Composites ◽  
The Stability

The mechanical reliability of ceramic matrix composites (CMCs) at elevated temperatures in oxidative environments is primarily dependent upon the chemical and structural stability of the fiber/matrix interface. Graphitic carbon coatings have traditionally been used to control the interfacial properties in CMCs, however, their use is limited in high temperature oxidative environments due to the loss of carbon and subsequent oxidation of the fiber and matrix. Thus, BN is being investigated as an alternative interfacial coating since it has comparable room temperature properties to carbon with improved oxidation resistance. The stability of BN interfaces in SiC/SiC composites is being investigated at elevated temperatures in either flowing oxygen or environments containing water vapor. The effect of several factors on BN stability, including crystallographic structure, extent of BN crystallization, and impurity content, are being evaluated.Nicalon™ fiber preforms were coated with ≈ 0.4 μm of BN by CVD using BCl3, NH3, and H2 at 1373 K. The coated preforms were densified using a forced-flow chemical vapor infiltration (FCVI) technique developed at ORNL.

Influence of Cobalt Addition on Microstructure and Damping Properties of Cu-Al-Ni Shape Memory Alloys

2020 ◽  
Vol 1010 ◽  
pp. 34-39
Author(s):  
Ying Ci Wee ◽  
Hamidreza Ghandvar ◽  
Tuty Asma Abu Bakar ◽  
Esah Hamzah
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Elastic Anisotropy ◽  
Mechanical Analysis ◽  
Damping Capacity ◽  
Damping Properties ◽  
Additional Element ◽  
Lower Temperature ◽  
Co Addition ◽  
High Degree

Copper-based shape memory alloys (SMAs) gaining attention due to their high damping properties during martensitic transformation and effective in energy dissipation which is applicable to damping application. However, copper-based SMAs such as the ternary Cu-Al-Ni are not easily deformed in the lower temperature martensitic phase which can be attributed to brittleness induced by coarse grain size, high degree of order and elastic anisotropy. Hence, this study aims to improve the properties of Cu-Al-Ni SMAs by addition of fourth alloying element. In this research, Cu-Al-Ni alloys with the addition of the fourth additional element, cobalt were prepared by casting. Microstructure characteristics of Cu-Al-Ni SMAs with and without Co addition were investigated via scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). Damping capacity was determined by dynamic mechanical analysis (DMA). It was found that the alloy with 0.7wt% of Co addition showed the best improvement on the damping properties.

Microstructure, mechanical properties and oxidation resistance of SiCf/SiC composites incorporated with boron nitride nanotubes

RSC Advances ◽  
2016 ◽  
Vol 6 (86) ◽  
pp. 83482-83492 ◽  
Author(s):  
Guangxiang Zhu ◽  
Shaoming Dong ◽  
Dewei Ni ◽  
Chengying Xu ◽  
Dengke Wang
Keyword(s):  
Mechanical Properties ◽  
Chemical Vapor ◽  
Boron Nitride Nanotubes ◽  
Chemical Vapor Infiltration ◽  
Raw Material ◽  
Boron Powder ◽  
Hierarchical Composites ◽  
Sic Composites ◽  
Polymer Impregnation

SiCf/BNNTs–SiC hierarchical composites were fabricated via firstly in situ growth of BNNTs on SiC fibers using boron powder as a raw material and then matrix densification by chemical vapor infiltration and polymer impregnation/pyrolysis methods.

scholarly journals Numerical Modeling Chemical Vapor Infiltration of SiC Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-11
Author(s):  
Yaochan Zhu ◽  
Eckart Schnack
Keyword(s):  
Phase Field ◽  
Field Model ◽  
Stokes Equations ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Competitive Growth ◽  
Field Equations ◽  
Model Framework ◽  
Sic Composites ◽  
Vapor Infiltration

The multiphase field model for chemical vapor infiltration (CVI) of SiC/SiC composites is developed in this study, thereby to reproduce the microstructure evolution during CVI process and to achieve better understanding of the effect of process parameters (e.g., temperature, pressure, etc.) on the final product. In order to incorporate the thermodynamics of methyltrichlorosilane (MTS) pyrolysis into phase field model framework, the reduced chemical reaction mechanism is adopted. The model consists of a set of nonlinear partial differential equations by coupling Ginzburg-Landau type phase field equations with mass balance equations (e.g., convection-diffusion equation) and the modified Navier-Stokes equations which accounts for the fluid motion. The microstructure of preferential codeposition of Si, SiC under high ratio of H2to MTS is simulated and the potential risk of blockage of the premature pores during isothermal CVI process is predicted. The competitive growth mechanism of SiC grains is discussed and the formation process of potential premature pore blockage is reproduced.

Emissivity of Silicon Carbide Composites as a Function of Temperature and Microstructure

1995 ◽  
Vol 410 ◽  
Author(s):  
Ming Sun ◽  
Isabel K. Lloyd
Keyword(s):  
Oxide Layer ◽  
Intelligent Control ◽  
Chemical Vapor ◽  
Sample Surface ◽  
Spectral Emissivity ◽  
Chemical Vapor Infiltration ◽  
Layer Formation ◽  
Microwave Assisted ◽  
Sic Fiber ◽  
Sic Composites

ABSTRACTSpectral emissivity normal to the sample surface was investigated as a potential intelligent control parameter for the manufacture of SiC fiber reinforced SiC composites by chemical vapor infiltration (CVI) and microwave assisted CVI. Results indicated that at temperatures between 600 and 1000°C and wavelengths between 1500 and 2100 nm emissivity was sensitive to the sample porosity. It also appeared to be sensitive to the thickness of the oxide layer on the composites. The emissivity was not very sensitive to temperature in this region. It was concluded that emissivity is promising as a probe of density during manufacturing. It may also be useful as a probe of oxide layer formation.

Sign in / Sign up

Export Citation Format

Share Document