Feasibility Study of a Tungsten Wire Reinforced Tungsten Matrix Composite with ZrOx Interfacial Coatings

TLDR: In this paper, a novel toughening method for tungsten is proposed based on reinforcement by Tungsten wires, which is analogous to that of fiber-reinforced ceramic matrix composites.

About: This article is published in Composites Science and Technology.The article was published on 2010-09-30 and is currently open access. It has received 67 citations till now. The article focuses on the topics: Fracture toughness & Tungsten.

Figures

Figure 1. Longitudinal sections of the as-fabricated interfaces with four different coatings.

Figure 4. Collected frP vs. l data obtained from the push-out curves of ZrOx single-layer coating together with the corresponding regression curve based on eq.(A2).

Figure 5. Collected p vs. H data obtained from the push-out curves of ZrOx single-layer coating together with the corresponding regression curve based on eq.(A4).

Figure 8. Pushed-out filaments of ZrOx single-layer coatings with three different thicknesses (a: 150 nm, b: 400 nm, c: 900 nm) together with the longitudinal sections of their corresponding interface domains.

Figure 3. Collected dP vs. H data obtained from the push-out curves of ZrOx single-layer coating together with the corresponding regression curve based on eq.(A1).

Figure 6. Small debris of the coating film attached on a broken interface.

Frequently asked questions

Q1. What are the contributions in "Feasibility study of a tungsten wire reinforced tungsten matrix composite with zrox interfacial coatings" ?

In this paper, a novel toughening method for tungsten is proposed based on reinforcement by tungsten wires. In this work, the authors evaluated six kinds of ZrOx-based interface coatings. 

Q2. What is the working principle of a high toughness tungsten?

The working principle of a high toughness FCMC is the non-plastic energy dissipation caused by controlled interfacial cracking and subsequent frictional sliding at the debonded fiber/matrix interface [5-8]. 

Q3. What is the popular choice for the plasma-facing material of nuclear fusion reactors?

Tungsten is currently the most favored candidate for the plasma-facing material of nuclear fusion reactors due to its refractory nature, excellent surface erosion resistance and good thermal conductivity. 

Q4. What is the effect of the matrix crack on the interfacial debonding?

As the applied load is increased, the interfacial debonding may continue followed by fiber pull-out and the matrix crack opens further in a controlled manner. 

Q5. What was the cause of the slight load jump?

A slight load jump was observed from C to D prior to the quasi-static progressive sliding stage which was caused by the delay of feedback signal to the load cell controller. 

Q6. How can the authors determine the shear strength of the filament/matrix interface?

The fracture energy and shear strength of the filament/matrix interface in Wf/W composites could be determined using the measured push-out test data and numerical fitting to theoretical equations. 

Q7. What are the estimated material parameters of the interfaces?

The estimated material parameters of the interfaces are shear strength dτ , radial roughness stress rσ , friction coefficient µ , (roughness-induced) frictional shear stress rτ and fracture energy (toughness) iΓ . 

Q8. What is the criterion for interfacial cracking?

According to the pioneering work of He and Hutchinson [19], interfacial cracking in a bi-material bond joint under tension requires thatthe ratio fi ΓΓ be smaller than a specific value depending on elastic mismatch between the two bonding partners. 

Q9. What is the i value of the interfacial ZrOx coating?

ACCEPTED MANUSCRIPT- 10 -5. The capability of the interfacial ZrOx coating to allow controlled crack deflection along the interface under tensile load could be demonstrated in a 3-point bending test on a miniaturized single-filament specimen. 

Q10. What is the shear strength of the matrix interface?

In the cases of the ZrOx single layer and the W/ZrOx single- and multi-layer coatings, the calibrated shear strength dτ ranged from 360 to 440 MPa whereasthe fracture energy iΓ ranged between 3 and 6 J/m². 

Q11. What is the main reason for the development of long fiberreinforced ceramic matrix composites?

Since last two decades, active research efforts have been conducted to develop long fiberreinforced ceramic matrix composites (FCMCs) for high-temperature structural applications. 

Q12. Why is tungsten a weak choice for plasma-facing fusion reactors?

There is a strong restriction in the chemical composition of plasma-facing tungsten, because the requirements of plasma compatibility and reduced activation have to be fulfilled. 

Q13. What is the way to test a tungsten composite?

ACCEPTED MANUSCRIPT- 3 -This toughening mechanism of FCMCs would also have validity for brittle tungsten provided that reinforcing fibers are strong enough and their interfaces are suitably engineered. 

Q14. How is the d value of the filament interpreted?

The calibrated dτ value of the ZrOx/filament interface has to be interpreted as effective shear strength averaged over the length.