TEM investigations of the fibre/matrix interface in SCS-6 SiC/Ti–25Al–10Nb–3V–1Mo composites

Yang, Youngsek; Dudek, H.J.; Kumpfert, J.

doi:10.1016/s1359-835x(97)00127-9

Cited by 30 publications

(12 citation statements)

References 15 publications

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“…The reaction kinetics can be described by the following equations [39]: x = kt 1/2 + b 0 , k = k 0 exp (− Q /2 RT ) where x is the thickness of the RL, t is time, k is the reaction rate constant, b 0 is the original thickness of the RL, R is the gas constant, Q is the activation energy, k 0 is the frequency factor, and T is the temperature. The reaction rate k was determined from the slope of the curves for fitting the thickness of RL at different times.…”

Section: Resultsmentioning

confidence: 99%

Interfacial Reactions and Mechanical Properties Studies of C-Coated and C/B4C Duplex-Coated SiC Fiber-Reinforced Ti2AlNb Composites

et al. 2019

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Continuous SiC fiber-reinforced Ti2AlNb matrix composites have a great potential for high-temperature aviation structure applications, and their properties strongly depend on the microstructure of the interfacial reaction layer. Notably, introducing diffusion barrier coatings has still been a popular strategy for optimizing the interfacial structure and interfacial properties of SiCf/Ti. In this work, C coating and C/B4C duplex coating were successfully fabricated onto SiC fibers via chemical vapor deposition (CVD), then consolidated into the SiCf/C/Ti2AlNb and the SiCf/C/B4C/Ti2AlNb composites, respectively, via hot isostatic pressing (HIP) under the condition of 970 °C, 150 MPa, 120 min, and finally furnace cooled to room temperature. The C- and C/B4C-dominated interfacial reactions in the SiCf/C/Ti2AlNb and the SiCf/C/B4C/Ti2AlNb were explored, revealing two different reaction products sequences: The different-sized TiC and the coarse-grained (Ti,Nb)C + AlNb3 for the SiCf/C/Ti2AlNb; and the fine-grained TiB2 + TiC, the needle-shaped (Ti,Nb)B2/NbB + (Ti,Nb)C, the coarse-grained (Ti,Nb)C + AlNb2 for the SiCf/C/B4C/Ti2AlNb. Annealing experiments were further carried out to verify the different reaction kinetics caused by C coating and C/B4C duplex coating. The reaction layer (RL)-dominated interfacial strength and tensile strength estimations showed that higher interface strength and tensile strength occurred in the SiCf/C/Ti2AlNb instead of the SiCf/C/B4C/Ti2AlNb, when the same failure mode of fiber push-out took place.

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Section: Resultsmentioning

confidence: 99%

Interfacial Reactions and Mechanical Properties Studies of C-Coated and C/B4C Duplex-Coated SiC Fiber-Reinforced Ti2AlNb Composites

et al. 2019

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“…It is also noteworthy that Si is absent in the RZ, as illustrated in Table 1 and Figure 6, suggesting that Si does not migrate from the SiC fiber across the C-coating to interact with the matrix. This avoids any reaction taking place between Si and matrix at the interface, which could easily occur and produce titanium silicide in the presence of Si and Ti at elevated temperatures, leading to fast thickening of the RZ at high temperatures and resulting in the loss of the interface stability and degradation of mechanical properties of the composites (Hall & Ni, 1995; Yang & Dudek, 1997; Yang et al, 1998 a , 1998 b ). Evidently, the protective C-coating on the SiC fiber surface maintains the stability of the interface in this composite system, as it shields the Si atoms within the fiber, hence prevents the interaction between the SiC fiber and the reactive metal atoms in the matrix.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the chemical reactions at the SiC fiber/Ti alloy matrix interface under fabrication and application conditions have been extensively investigated in order to obtain insight into the microstructure evolution at the interface under such conditions, so that the TMCs fabrication process can be optimized and, consequently, their performance improved. Specifically, the thermal stability and compatibility of the fiber/matrix interface, and the microstructure evolution of the interfacial reaction zone (RZ) upon isothermal exposure are the focus of several investigations (Fromentin et al, 1996; Yang et al, 1998 b ; Li et al, 2011; Ngai et al, 2011; Lacoste et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

On Interfacial Microstructure Evolution in an Isothermally Exposed SiC Fiber-Reinforced Ti-17 Matrix Composite

Fan¹,

Zhou

2019

Microsc Microanal

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The kinetics and mechanisms of interface reactions in a unidirectional continuous SiC fiber-reinforced Ti-17 matrix composite were investigated using transmission electron microscopy and scanning electron microscopy. It was found that a reaction zone (RZ) consisting of two-layered TiC-type carbide forms at the fiber/matrix interface during fabrication of the composite. After isothermal exposure at elevated temperatures, the two-layered TiC-type carbide is inherited, and a new TiC-type carbide layer forms within the RZ after exposure at temperatures lower than 900°C, while a new Ti3C2-type carbide layer forms after exposure at 900°C. It was also observed that the growth of RZ is a diffusion-controlled and temperature-dependent process, obeying the Fick's law-based parabolic relationship and the Arrhenius equation. Two material constants, the temperature-independent rate constant k0 and activation energy Q, are determined as 31.5 × 10−4µm/s1/2 and 49.9 kJ/mol, respectively.

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“…For example, by investigating the interfacial reaction phenomena, the stability and compatibility of the relevant materials can be evaluated. The outcome of such evaluation provides the necessary knowledge for interface design in TMCs for optimising the processing/manufacturing technology and improving product performance (Fromentin et al, 1996;Lacoste et al, 2015;Li et al, 2011;Ngai et al, 2011;Yang et al, 1998b).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

A study of interface reaction zone in a SiC fibre/Ti-17 composite

Fan

Zhou

2018

Micron

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The interface reaction zone (RZ) in a unidirectional continuous carbon-coated SiC fibre reinforced Ti-17 titanium alloy composite is investigated. Micro-computed tomography (CT), scanning and transmission electron microscopy are employed to characterize the fibre/matrix interface. It is revealed that the interface RZ is a 400 nm thick titanium carbide (TiC) layer which is composed of two sublayers, a 60 nm thick fine-grained sublayer and an approximate 340 nm thick coarse-grained sublayer. The RZ is formed through chemical reaction between carbon coating on the SiC fibre surface and Ti, Zr and Sn in the alloy matrix. The reaction is controlled by atom diffusion occurring at the fibre/matrix interface. However, in the reaction process, Al, Cr and Mo in the matrix are rejected and piled up in front of the RZ on the matrix side. A structure model is proposed to describe the formation mechanism of the interface RZ.

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TEM investigations of the fibre/matrix interface in SCS-6 SiC/Ti–25Al–10Nb–3V–1Mo composites

Cited by 30 publications

References 15 publications

Interfacial Reactions and Mechanical Properties Studies of C-Coated and C/B4C Duplex-Coated SiC Fiber-Reinforced Ti2AlNb Composites

Interfacial Reactions and Mechanical Properties Studies of C-Coated and C/B4C Duplex-Coated SiC Fiber-Reinforced Ti2AlNb Composites

On Interfacial Microstructure Evolution in an Isothermally Exposed SiC Fiber-Reinforced Ti-17 Matrix Composite

A study of interface reaction zone in a SiC fibre/Ti-17 composite

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