The Influence of Cyclic Sintering on the Structure and Mechanical Properties of Tungsten Heavy Alloy

Abstract The results of structure and mechanical properties investigations of tungsten heavy alloy (THA) after cyclic sintering are presented. The material for study was prepared using liquid phase sintering of mixed and compacted powders in hydrogen atmosphere. The specimens in shape of rods were subjected to different number of sintering cycles according to the heating schemes given in the main part of the paper From the specimens the samples for mechanical testing and structure investigations were prepared. It follows from the results of the mechanical studies, that increasing of sintering cycles lead to decrease of tensile strength and elongation of THA with either small or no influence on yield strength. In opposite to that, the microstructure observations showed that the size of tungsten grain increases with number of sintering cycles. Moreover, scanning electron microscope (SEM) observations revealed distinctly more trans-granular cleavage mode of fracture in specimens subjected to large number of sintering cycles compared with that after one or two cycles only.

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Preliminary Study of the Rhenium Addition on the Structure and Mechanical Properties of Tungsten Heavy Alloy

Materials ◽

10.3390/ma14237365 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7365

Author(s):

Paweł Skoczylas ◽

Mieczysław Kaczorowski

Keyword(s):

Mechanical Properties ◽

Mechanical Property ◽

Hydrogen Atmosphere ◽

Liquid Phase Sintering ◽

Heavy Alloy ◽

Tungsten Heavy Alloy ◽

Preliminary Study ◽

Rhenium Addition ◽

Structure Investigations ◽

Mechanical Studies

The results of structure and mechanical property investigations of tungsten heavy alloy (THA) with small additions of rhenium powder are presented. The material for the study was prepared using liquid phase sintering (LPS) of mixed and compacted powders in a hydrogen atmosphere. From the specimens, the samples for mechanical testing and structure investigations were prepared. It follows from the results of the microstructure observations and mechanical studies, that the addition of rhenium led to tungsten grain size decreasing and influencing the mechanical properties of W-Ni-Fe-Co base heavy alloy.

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Effect of Composition on Tensile and Impact Properties of Tungsten-Based Heavy Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.863.40 ◽

2016 ◽

Vol 863 ◽

pp. 40-44 ◽

Cited By ~ 1

Author(s):

P.V. Satyanarayana ◽

R. Sokkalingam ◽

K. Sivaprasad ◽

A.K. Mukherjee

Keyword(s):

Mechanical Properties ◽

Particle Size ◽

Tensile Strength ◽

Weight Fraction ◽

Liquid Phase Sintering ◽

Heavy Alloy ◽

Tungsten Heavy Alloy ◽

Tungsten Particle ◽

Lower Elongation ◽

Powder Metallurgy Route

Tungsten heavy alloy of two different compositions (93W-4.0Ni-2.0Co-1.0Fe and 90W-6.1Ni-3.0Fe-0.5Co-0.4Mo in wt%) was synthesized in conventional powder metallurgy route through the liquid phase sintering. Studies have been carried out on the effect of alloying elements, tungsten particle size, and amount of matrix on mechanical properties. The alloy with 93% W had shown the higher tensile strength value and lower elongation along with double the value of impact energy than that of 90% W due to lower tungsten particle size and weight fraction in addition to an increase in cobalt and increase in ratio of iron to nickel. Relatively higher porosity could also have resulted in reduced properties.

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The Effect of Cold Swaging of Tungsten Heavy Alloy with the Composition W91-6Ni-3Co on the Mechanical Properties

Materials ◽

10.3390/ma14237300 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7300

Author(s):

Paweł Skoczylas ◽

Olgierd Goroch ◽

Zbigniew Gulbinowicz ◽

Andrzej Penkul

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Tensile Strength ◽

Powder Metallurgy ◽

Liquid Phase ◽

Cold Work ◽

Heavy Alloy ◽

Tungsten Heavy Alloy ◽

Strength Parameters ◽

Microhardness And Microstructure

The paper presents the results of studies on the effects of heat treatment and cold-work parameters on the mechanical properties and microstructure of the tungsten heavy alloy (WHA) with the composition W91-6Ni-3Co. Tungsten heavy alloy (WHA) is used in conditions where strength, high density, and weight are required. The material for testing as rod-shaped samples was produced by the method of powder metallurgy and sintering with the participation of the liquid phase and then subjected to heat treatment and cold swaging. The study compares the effect of degree deformation on the strength, hardness, microhardness, and microstructure of WHA rods. The conducted tests showed that heat treatment and cold-work allowed to gradually increase the strength parameters, i.e., tensile strength , yield strength , elongation ε, hardness, and microhardness. These processes made it possible to increase the tensile strength by over 800 MPa (from the initial 600 MPa after sintering to the final value of over 1470 MPa after heat treatment with cold swaging deformation with reduction of 30%) and the hardness from 32 to 46 HRC.

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Microstructure and mechanical properties of a rotary friction welded tungsten heavy alloy

Materials Testing ◽

10.3139/120.111307 ◽

2019 ◽

Vol 61 (3) ◽

pp. 209-212

Author(s):

Ramachandran Damodaram ◽

Gangaraju Manogna Karthik ◽

Sree Vardhan Lalam

Keyword(s):

Mechanical Properties ◽

Heavy Alloy ◽

Tungsten Heavy Alloy ◽

Microstructure And Mechanical Properties

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Analysis of PLA Composite Filaments Reinforced with Lignin and Polymerised-Lignin-Treated NFC

Polymers ◽

10.3390/polym13132174 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2174

Author(s):

Diana Gregor-Svetec ◽

Mirjam Leskovšek ◽

Blaž Leskovar ◽

Urška Stanković Elesini ◽

Urška Vrabič-Brodnjak

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Scanning Electron Microscopy ◽

Tensile Strength ◽

Glassy State ◽

Nanofibrillated Cellulose ◽

Dynamic Mechanical Properties ◽

Initial Modulus ◽

Surface Modified ◽

Scanning Electron

Polylactic acid (PLA) is one of the most suitable materials for 3D printing. Blending with nanoparticles improves some of its properties, broadening its application possibilities. The article presents a study of composite PLA matrix filaments with added unmodified and lignin/polymerised lignin surface-modified nanofibrillated cellulose (NFC). The influence of untreated and surface-modified NFC on morphological, mechanical, technological, infrared spectroscopic, and dynamic mechanical properties was evaluated for different groups of samples. As determined by the stereo and scanning electron microscopy, the unmodified and surface-modified NFCs with lignin and polymerised lignin were present in the form of plate-shaped agglomerates. The addition of NFC slightly reduced the filaments’ tensile strength, stretchability, and ability to absorb energy, while in contrast, the initial modulus slightly improved. By adding NFC to the PLA matrix, the bending storage modulus (E’) decreased slightly at lower temperatures, especially in the PLA samples with 3 wt% and 5 wt% NFC. When NFC was modified with lignin and polymerised lignin, an increase in E’ was noticed, especially in the glassy state.

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Characterization and Utilization of Coconut Fibers of the Caribbean

MRS Proceedings ◽

10.1557/opl.2014.764 ◽

2014 ◽

Vol 1611 ◽

pp. 95-104 ◽

Cited By ~ 2

Author(s):

Nadira Mathura ◽

Duncan Cree ◽

Ryan P. Mulligan

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Electron Micrographs ◽

Saline Water ◽

Gauge Length ◽

Scanning Electron Micrographs ◽

Coir Fiber ◽

Coir Fibers ◽

The Caribbean ◽

Scanning Electron

ABSTRACTIn many tropical countries coconut (coir) fiber production is a major source of income for rural communities. The Caribbean has an abundance of coconuts but research into utilizing its by-products is limited. Environmentally friendly coir fibers are natural polymers generally discarded as waste material in this region. Research has shown that coir fiber from other parts of the world has successfully been recycled. This paper therefore investigates the mechanical properties of Caribbean coir fiber for potential applications in civil engineering.Approximately four hundred fibers were randomly taken from a coir fiber stack and subjected to retting in both distilled and saline water media. The mechanical properties of both the retted and unretted coir fibers were evaluated at weekly increments for a period of 3 months. Tensile strength test, x-ray diffraction analysis and scanning electron micrographs were used to assess trends and relationships between fiber gauge lengths, diameter, tensile strength and Young’s modulus. Diameters ranged between 0.11 mm-0.46 mm, while fiber samples were no longer than 250 mm in length. The tensile strength and strain at break decreased as the gauge length increased for both unretted and retted fibers. The opposite occurred for the relationship between the gauge length and Young’s modulus. Additionally, the tensile strength and modulus decreased as the fiber diameter increased. Neither distilled nor saline water improved the coir fiber’s crystalline index. Scanning electron micrographs qualitatively assessed fiber surfaces and captured necking and microfibril degradation at the fractured ends.The analysis revealed that the tensile strength, modulus, strain at break and crystallinity properties of the Caribbean coir fibers were comparable to commercially available coir fiber which are currently being used in many building applications.

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Preparation and Mechanical Properties of Graphene Oxide: Cement Nanocomposites

The Scientific World JOURNAL ◽

10.1155/2014/276323 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 83

Author(s):

Fakhim Babak ◽

Hassani Abolfazl ◽

Rashidi Alimorad ◽

Ghodousi Parviz

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Graphene Oxide ◽

Cement Mortar ◽

Cement Matrix ◽

Cement Composites ◽

Xrd Diffraction ◽

Calcium Silicate Hydrates ◽

The Matrix ◽

Scanning Electron

We investigate the performance of graphene oxide (GO) in improving mechanical properties of cement composites. A polycarboxylate superplasticizer was used to improve the dispersion of GO flakes in the cement. The mechanical strength of graphene-cement nanocomposites containing 0.1–2 wt% GO and 0.5 wt% superplasticizer was measured and compared with that of cement prepared without GO. We found that the tensile strength of the cement mortar increased with GO content, reaching 1.5%, a 48% increase in tensile strength. Ultra high-resolution field emission scanning electron microscopy (FE-SEM) used to observe the fracture surface of samples containing 1.5 wt% GO indicated that the nano-GO flakes were well dispersed in the matrix, and no aggregates were observed. FE-SEM observation also revealed good bonding between the GO surfaces and the surrounding cement matrix. In addition, XRD diffraction data showed growth of the calcium silicate hydrates (C-S-H) gels in GO cement mortar compared with the normal cement mortar.

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Effect of Annealing Process on the Mechanical Properties of X70 Pipeline Steel

MATEC Web of Conferences ◽

10.1051/matecconf/201818602001 ◽

2018 ◽

Vol 186 ◽

pp. 02001

Author(s):

Teng-wei Zhu ◽

Cheng-liang Miao ◽

Zheng Cheng ◽

Zhipeng Wang ◽

Yang Cui ◽

...

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Scanning Electron Microscopy ◽

Tensile Strength ◽

Annealing Temperature ◽

Pipeline Steel ◽

Annealing Process ◽

X70 Pipeline Steel ◽

Grain Sizes ◽

Scanning Electron

The influence of the mechanical properties of X70 pipeline steel under different annealing temperature was studied. The corresponding microstructure was investigated by the Field Emission Scanning Electron Microscopy. The results showed that the yield strength and the tensile strength both experienced from rise to decline with the increase of annealing temperature. The grain sizes were coarse and a large amount of cementite precipitated due to preserving temperature above 550 °, which induced matrix fragmentation and deteriorate the -10 ° DWTT Toughness. There were little changes on the microstructure and mechanical properties when the annealing temperature was under 500 °.

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