The influence of dynamic shear loading on plastic deformation and microstructure of tungsten single crystals

Chiem, C.Y.; Lee, W.S.

doi:10.1016/0921-5093(94)90329-8

Cited by 28 publications

(8 citation statements)

References 13 publications

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“…C OMPOSITE STRUCTURES SUBJECTED to high strain rate (HSR) dynamic loading have become of a great interest to many researchers, specifically in the defense industry. In recent years some investigators have addressed the strain rate effects on fiber reinforced polymer matrix composites (PMC) [1][2][3][4][5][6][7][8]. It appears from their studies that the overall rate-dependence of the composites, depends to a greater or lesser extent, on the rate dependence of the various phases; the reinforcement configuration, and the type and direction of loading.…”

Section: Introductionmentioning

confidence: 99%

High Strain Rate Responses and Failure Analysis in Polymer Matrix Composites – An Experimental and Finite Element Study

Haque

Ali

2005

Journal of Composite Materials

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Compressive properties and failure analysis of unidirectional and plain weave S2-glass/vinylester composites under high strain rate (HSR) loading have been investigated using the Split Hopkinson Pressure Bar (SHPB) technique. A systematic experimental approach has been adopted in this work to identify the damage progression at various stress levels and the strain rate effects on composites. The classical SHPB apparatus has been incorporated by a wave-trapping mechanism to apply a predetermined level of impact loading and to restrict the repeated loading. This facilitates identification of the microstructural damage progression during the loading period. The stress–strain responses at various strain rates in all three principal directions are investigated and the relevant failure modes are also identified by microscopic examinations. The quasi-static compressive strength, the strain to failure, and the elastic moduli are compared with SHPB test results to determine the shift in the failure mechanism. The compressive strength and failure strain for both unidirectional and plain weave composites are observed to be rate dependent. Such rate dependencies of compressive response are analyzed and correlation between the failure modes and the rate effects on composites are established. Finally, a three-dimensional transient finite element analysis (FEA) has also been carried out for unidirectional composites under high strain rate loading in order to have a thorough understanding of the failure mechanisms. Loads are applied in thickness, fiber and transverse of fiber directions and corresponding stress contours are simulated. The FEA prediction of the stress–strain behavior in all the three principal directions of loading correlates well with the high strain rate experimental results.

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Section: Introductionmentioning

confidence: 99%

High Strain Rate Responses and Failure Analysis in Polymer Matrix Composites – An Experimental and Finite Element Study

Haque

Ali

2005

Journal of Composite Materials

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“…Recent studies on developing tungsten penetrator to have a deformation behavior that can induce heavy-alloy penetrators have focused on promoting selfself-sharpening as well as possess sufficient fracture toughsharpening. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] In depleted uranium alloy penetrators, this ness to minimize fragmentation during high-speed phenomenon is known to be associated with the formation impact. [22,23] For this end, it is necessary to correlate the of adiabatic shear bands.…”

Section: Introductionmentioning

confidence: 99%

Dynamic deformation behavior of an oxide-dispersed tungsten heavy alloy fabricated by mechanical alloying

Park

Kim

Lee

et al. 2001

Metall Mater Trans A

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The objective of this study is to investigate the dynamic deformation and fracture behavior of an oxide-dispersed (OD) tungsten heavy alloy fabricated by mechanical alloying (MA). The tungsten alloy was processed by adding 0.1 wt pct Y 2 O 3 powders during MA, in order to form fine oxides at triple junctions of tungsten particles or at tungsten/matrix interfaces. Dynamic torsion tests were conducted for this alloy, and the test data were compared with those of a conventional liquid-phase sintered (LPS) specimen. A refinement in tungsten particle size could be obtained after MA and multistep heat treatment without an increase in the interfacial area fraction between tungsten particles. The dynamic test results indicated that interfacial debonding between tungsten particles occurred over broad deformed areas in this alloy, suggesting the possibility of adiabatic shear-band formation. Also, oxide dispersion was effective in promoting interfacial debonding, since the fine oxides acted as initiation sites for interfacial debonding. These findings suggest that the idea of forming fine oxides would be useful for improving self-sharpening and penetration performance in tungsten heavy alloys.

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“…This results are fully consistent with the yield stress values obtained for the recrystallized wire. In addition, Chiem et al [40] performed shear deformation applied to single crystal cylindrical W rods at room temperature, and obtained the yield shear stress to be about 200-220 MPa for the rods with However, the instrumented micro-indentation experiments were performed by Uytdenhouwen [41] on the forged tungsten rods in a wide temperature range, including room temperature testing. The yield stress extracted from those tests at RT was reported to be in the range 1200-1500 MPa, which falls in the range of the yield stress of the as-received wires obtained in the current work.…”

Section: Discussionmentioning

confidence: 99%

“…Experimental data for "Recrystallized" material correspond to the data obtained for the sample annealed at 2100°C. Black squares presents the experimental data obtained for single crystal pure tungsten by Brunner [38] and Chiem et al [40], as explained in the text.…”

Section: Discussionmentioning

confidence: 99%

Correlation of microstructural and mechanical properties of K-doped tungsten fibers used as reinforcement of tungsten matrix for high temperature applications

Terentyev

Renterghem

Tanure

et al. 2019

International Journal of Refractory Metals and Hard Materials

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Reinforcement of tungsten by tungsten fibers (Wf) is considered an attractive option to mitigate the intrinsic brittleness of this material and to possibly extend the operational temperature window to ensure safe operation of the plasma facing component. By now, it has been demonstrated that tungsten fiber-reinforced tungsten composites (Wf/W)acquire pseudo ductility even at room temperature, and crack propagation is determined by the interaction of the fibers with the propagating crack. In view of strong temperature oscillations, expected during operation in the fusion plasma, the mechanical properties of tungsten fibers annealed at different temperatures (up to 2300°C) were assessed, and the role of potassium (K) doping on the modification of the mechanical properties of asannealed wires was studied. While K-doping was found to delay the brittleness induced by heat exposure at least up to 1600°C, still a strong reduction of the fiber strength was observed in tests performed at elevated temperatures. In this work, we investigate the reasons for this effect by performing scanning electron microscopy coupled with electron backscatter diffraction measurements. The longitudinal and transversal cross-sections of W fibers were analyzed to deduce the morphology and size distribution of the grains. Consistent with the mechanical data, we found that annealing at 2100°C resulted in the full recrystallization of the elongated grains, otherwise formed due to the extrusion fabrication process. Even at 1900°C, the longitudinal cross-section still exhibits elongated grains. The transversal shape of the grains undergoes a change from needle-like fine structure to equiaxed grain shape upon annealing above 1600°C. Few scans done for 2300°C annealed wire revealed that the microstructure contains one or several grains with a dimension of 70-150 µm. The obtained results are discussed and analyzed in the frame of mechanistic model connecting microstructure with the mechanical response.

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The influence of dynamic shear loading on plastic deformation and microstructure of tungsten single crystals

Cited by 28 publications

References 13 publications

High Strain Rate Responses and Failure Analysis in Polymer Matrix Composites – An Experimental and Finite Element Study

High Strain Rate Responses and Failure Analysis in Polymer Matrix Composites – An Experimental and Finite Element Study

Dynamic deformation behavior of an oxide-dispersed tungsten heavy alloy fabricated by mechanical alloying

Correlation of microstructural and mechanical properties of K-doped tungsten fibers used as reinforcement of tungsten matrix for high temperature applications

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