Effect of tungsten content on microstructure and quasi-static tensile fracture characteristics of rapidly hot-extruded W–Ni–Fe alloys

Gong, Xing; Fan, Jing; Ding, Fei; Song, Min; Huang, Baiyun

doi:10.1016/j.ijrmhm.2011.06.014

Cited by 59 publications

(16 citation statements)

References 25 publications

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“…Since the sintering temperature selected is 1480°C, relatively smaller average tungsten grain size (  16.8 micron) was observed in the alloys. Due to the differences in liquid phase sintering temperature and sintering time, higher values of tungsten grain size ( 40 micron) have been reported in the literature for alloys with similar composition [15,23]. Similar to the work reported in the literature [14,15], swaging after sintering led to a slight increase in longitudinal tungsten grain size and a reduction in transverse tungsten grain size ( Table 2).…”

Section: Resultssupporting

confidence: 75%

“…In the processing of tungsten heavy alloys, for applications which require higher tensile strength and hardness, post sintering operations such as cold rolling [11], swaging [12][13][14][15][16][17][18][19][20] and extrusion [21][22][23] have been used. Cold deformation of sintered tungsten heavy alloys increases the dislocation density which in turn leads to improvement in tensile strength and hardness due to strain hardening.…”

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confidence: 99%

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Effect of swaging on microstructure and tensile properties of W–Ni–Fe alloys

Durlu

Çalışkan

Bor

2014

International Journal of Refractory Metals and Hard Materials

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Section: Resultssupporting

confidence: 75%

mentioning

confidence: 99%

Effect of swaging on microstructure and tensile properties of W–Ni–Fe alloys

Durlu

Çalışkan

Bor

2014

International Journal of Refractory Metals and Hard Materials

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“…Samples were prepared for microstructural evaluation by cutting, mounting, grinding and polishing to a 0.3µm surface finish using standard metallographic procedures. The microstructures were observed by scanning electron microscope (SEM) type TESCAN after etching using (HNO3 15 ml, HF 3 ml, H2O 80 ml) as an etchant [8]. The micrographs were quantitatively analyzed using an image analyzer to measure the size and volume fraction of tungsten particles, the matrix fraction, the connectivity and the contiguity, which greatly influence the properties of tungsten heavy alloys.…”

Section: Characterization Of Samplesmentioning

confidence: 99%

Effect of Applying Hot Isostatic Pressing on the Microstructure and Mechanical Properties of Tungsten Heavy Alloys

Abdallah¹,

Fayed²,

Abdo³

et al. 2017

Eng. Sci. and Milit. Techno.

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The objective of this experimental study is to investigate the effect of hot isostatic pressing (HIP) on the density, mechanical properties and microstructure of pre-sintered specimens of 93%W-4.9%Ni-2.1%Fe alloy. To achieve this target, Containerless HIPing at temperature 1300°C was applied. While, the HIPing pressure was varied from 100 MPa to 150 MPa. Elemental powders were mixed using double cone mixer for 2 hours. Cold Isostatic Pressing was applied for consolidation of metal powders into green compacts to obtain cylindrical tensile and impact specimens at 200MPa using rubber molds. Finally, the specimens were sintered under vacuum atmosphere at 1470ºC for 30 minutes. The applied HIPing temperature was chosen to be 1300°C. While, the applied HIPing pressure was varied from 100MPa to 150MPa, in order to study the effect of HIPing pressure on the mechanical properties, and the soaking time was 60 minutes. The effect of applying Hot Isostatic Pressing was characterized in terms of density, hardness, impact resistance and tensile properties, then compared with samples in the as sintered state. The microstructure analysis indicates that connectivity, contiguity and average grain size increase, while micropores were almost eliminated, this took place when applying a HIPing cycle at 1300°C under 100MPa for 60 minutes. On the other hand, When the HIPing pressure was increased to 150 MPa, a severe plastic deformation of the tungsten grains takes place, contiguity seriously increases leading to inhomogeneous microstructure. The tensile strength and hardness increase when applying hot isostatic pressing of 100MPa, compared with its value in the as sintered state, Further increase in HIPing pressure up to 150MPa decreases theses values of strength and hardness, relative to its value at 100MPa. On the contrary, ductility and impact resistance decrease continuously when applying a HIPing cycles under 100MPa and 150MPa respectively, relative to its value in the as sintered state.

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“…Elemental powders of tungsten, nickel and iron were mixed to produce a mixture with the composition of 93W-4.9Ni-2.1Fe in weight percent. This content of tungsten is widely used to achieve the highest mechanical properties, while, the Ni to Fe ratio is typically maintained to7/3 to avoid the formation of brittle intermetallic phases [9,10,4,5]. The different powders were mixed using planetary mixer for 5 hours, to insure homogeneous mixing.…”

Section: Preparation Of Sintered Specimensmentioning

confidence: 99%

Effect of Processing Parameters on the Mechanical and Structure Properties of 93W–4.9Ni–2.1Fe Tungsten Heavy Alloy

Abdallah¹,

Fayed²,

Abdo³

et al. 2013

International Conference on Aerospace Sciences and Aviation Tec

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The objective of this experimental study is to investigate the effect of the main compaction and sintering parameters on the micro-structure and the mechanical properties of the liquid phase sintered 93%wt.W-4.9%wt.Ni-2.1%wt.Fe tungsten heavy alloy aiming at determining the optimum values of these parameters. Elemental powders were mixed using planetary mixer for 5 hours to ensure suitable homogeneity. Uni-axial compaction was applied to obtain standard tensile and impact specimens using compaction pressures ranging from 50MPa to 300MPa. Vacuum liquid phase sintering was carried out under different temperatures from 1460 ᵒ C up to 1500 ᵒ C and sintering time from 30 minutes up to 120 minutes. The effect of these parameters was characterized in terms of density, hardness, impact resistance and tensile properties. Microstructure variations, notably grain size, matrix volume fraction and contiguity were measured and used to explain the effect of sintering temperature and time on the properties. The obtained results indicated that optimum hardness and impact resistance can be obtained at a compaction pressure of about 200 MPa. As the sintering temperature increases, the grain size and volume fraction of matrix increase, while the contiguity decreases. As a result of these micro-structural changes, strength and hardness decrease. On the other hand, ductility and impact resistance increase with sintering temperature to some maximum at 1480 ᵒ C. At further increase of this temperature, grain growth becomes the dominant factor leading to a sensible decrease in all properties. The effect of sintering time on mechanical properties is related to grain growth and pore coarsening mechanisms. It is generally observed that strength and ductility decrease after sintering over 90 minutes at 1480 ᵒ C. It was also noticed that the ductility is more sensitive to sintering time and is reduced sharply with prolonged holding at the sintering temperature. It can be concluded that the mechanical properties of tungsten heavy alloys are sensitive to the processing cycle and are adversely affected by residual porosity. Moreover, tungsten grain size plays an important role in dictating the failure mode during tensile testing. If tungsten grain size is large interface failure is predominant. However, as the grain size decreases, fracture mode changes gradually from interface failure to matrix failure and then to tungsten grain cleavage failure.

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Effect of tungsten content on microstructure and quasi-static tensile fracture characteristics of rapidly hot-extruded W–Ni–Fe alloys

Cited by 59 publications

References 25 publications

Effect of swaging on microstructure and tensile properties of W–Ni–Fe alloys

Effect of swaging on microstructure and tensile properties of W–Ni–Fe alloys

Effect of Applying Hot Isostatic Pressing on the Microstructure and Mechanical Properties of Tungsten Heavy Alloys

Effect of Processing Parameters on the Mechanical and Structure Properties of 93W–4.9Ni–2.1Fe Tungsten Heavy Alloy

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