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

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7365
Author(s):  
Paweł Skoczylas ◽  
Mieczysław Kaczorowski

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.

2016 ◽  
Vol 16 (4) ◽  
pp. 131-136 ◽  
Author(s):  
P. Skoczylas ◽  
M. Kaczorowski

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.


2016 ◽  
Vol 863 ◽  
pp. 40-44 ◽  
Author(s):  
P.V. Satyanarayana ◽  
R. Sokkalingam ◽  
K. Sivaprasad ◽  
A.K. Mukherjee

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.


2019 ◽  
Vol 61 (3) ◽  
pp. 209-212
Author(s):  
Ramachandran Damodaram ◽  
Gangaraju Manogna Karthik ◽  
Sree Vardhan Lalam

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4200 ◽  
Author(s):  
Adéla Macháčková ◽  
Ludmila Krátká ◽  
Rudolf Petrmichl ◽  
Lenka Kunčická ◽  
Radim Kocich

This study focuses on numerical prediction and experimental investigation of deformation behaviour of a tungsten heavy alloy prepared via powder metallurgy and subsequent cold (20 °C) and warm (900 °C) rotary swaging. Special emphasis was placed on the prediction of the effects of the applied induction heating. As shown by the results, the predicted material behaviour was in good correlation with the real experiment. The differences in the plastic flow during cold and warm swaging imparted differences in structural development and the occurrence of residual stress. Both the swaged pieces exhibited the presence of residual stress in the peripheries of W agglomerates. However, the NiCO matrix of the warm-swaged piece also exhibited the presence of residual stress, and it also featured regions with increased W content. Testing of mechanical properties revealed the ultimate tensile strength of the swaged pieces to be approximately twice as high as of the sintered piece (860 MPa compared to 1650 MPa and 1828 MPa after warm and cold swaging, respectively).


Author(s):  
Ondřej KovářÍk ◽  
Jaroslav Čech ◽  
Jan Cizek ◽  
Jakub Klečka ◽  
Michal Hajíček

Abstract Tungsten heavy alloy (WHA) of W-Ni composition was deposited from a blend of standard thermal spray powders using radio frequency inductively coupled plasma torch (RF-ICP) in a protective atmosphere. The deposit (RF WHA) contained a fully developed WHA structure; i.e.; spherical W particles embedded in a Ni-rich matrix. The bending tensile strength Rm; bending yield strength Rp;0.2; and elastic modulus of the deposit were compared with two W-Ni-Co references fabricated by powder metallurgy (PM WHA) via sintered and quenched (PMSQ); and forged and annealed (PM-FA). While the RF deposit properties are comparable with the PM-SQ reference; the PMFA exhibited higher mechanical properties. The deposit showed very limited ductility A < 3%. The fatigue crack growth rate in the deposit measured in bending (R < -1) was comparable to the PM-SQ reference material in the near-threshold region whereas the forged PM-FA had significantly better fatigue performance. In the near-threshold fatigue regime; the crack growth took place in the Ni-rich matrix. In the Paris regime; the similar fracture mode was observed; with the exception of PM-SQ; where the tungsten particles fracture contributed significantly. The static failure was exclusively trans-particle in RF WHA; while both PM WHAs failed by a mix of ductile matrix failure and trans-particle cleavage fracture. The fracture toughness of the deposit was significantly lower than the references. These early results indicate that RF-plasma spray is a suitable and efficient manufacturing method for production of WHA materials; however with limited mechanical properties in some aspects.


2008 ◽  
Vol 22 (09n11) ◽  
pp. 1201-1208 ◽  
Author(s):  
CHEOL SOO KIM ◽  
CHANG WOOK KIM

In this study, we analyzed the relation between mechanical and ballistic properties of several engineering ceramics that were expected to be used as armor materials. After the measurements of mechanical properties (Young's modulus, density, hardness, flexural strength and toughness), we measured the ballistic properties against a long rod KE projectile ( L / D =10.7, Kinetic Energy, tungsten heavy alloy) and copper jet projectile (40mm shaped charge warhead). The ballistic properties were generally increased as the increasing ratio of mechanical properties and density. As the HEL/density ratio was increased, it especially appeared that the ballistic properties were lineally increased.


2015 ◽  
Vol 15 (4) ◽  
pp. 45-50
Author(s):  
M. Kaczorowski ◽  
P. Skoczylas ◽  
A. Krzyńska

Abstract The results of structure observations of Ni base superalloy subjected to long-term influence of high pressure hydrogen atmosphere at 750K and 850K are presented. The structure investigation were carried out using conventional light-, scanning- (SEM) and transmission electron microscopy (TEM). The results presented here are supplementary to the mechanical studies given in part I of this investigations. The results of study concerning mechanical properties degradation and structure observations show that the differences in mechanical properties of alloy subjected different temperature are caused by more advanced processes of structure degradation during long-term aging at 850K, compare to that at 750K. Higher service temperature leads to formation of large precipitates of δ phase. The nucleation and growth of needle- and/or plate-like, relative large delta precipitates proceed probably at expense strengthening γʺ phases. Moreover, it can’t be excluded that the least stable γʺ phase is replaced with more stable γʹ precipitates. TEM observations have disclosed differences in dislocation structure of alloy aged at 750K and 850K. The dislocation observed in alloy subjected to 750K are were seldom observed only, while in that serviced at high stress and 850K dislocation array and dislocation cell structure was typical.


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