The Effect of Sintering Conditions on the Microstructural Parameters of Particle Composites

2010 ◽  
Vol 129-131 ◽  
pp. 438-444
Author(s):  
S.H. Islam ◽  
M.A. Al-Eshaikh
Keyword(s):  
Sintering Temperature ◽  
Hydrogen Atmosphere ◽  
Intermetallic Phases ◽  
Microstructural Parameters ◽  
Heavy Alloys ◽  
Tungsten Heavy Alloys ◽  
Different Temperatures ◽  
Sintering Conditions ◽  
Co Alloys ◽  
Strength And Ductility

Tungsten heavy alloys are particle composites; they occupy a unique position in materials because of their combination of high density, strength and ductility. The main focus of this study was to examine the effect of sintering conditions (temperature and time) on the microstructural parameters of tungsten heavy alloys. Alloys composed of 88%, 93% and 95% wt. of tungsten and either Ni: Fe (in the ratio of 7:3) or Ni: Co (in the ratio of 7:3) were consolidated into green compacts. Samples of each of the six resulting alloys were sintered in hydrogen atmosphere at different temperatures for different sintering holding times. The microstructural parameters of both types were found to be roughly similar at each temperature and holding time. At higher sintering temperature and longer sintering holding times there was a matrix gradient and the formation of FeNi intermetallic phases at tungsten matrix interfaces. The microstructural parameters showed that the W-Ni-Co alloys may have some advantage as a result of their small tungsten grains and the lower contiguity.

Microstructure and Tensile Properties of Tungsten Heavy Alloys

2007 ◽  
Vol 534-536 ◽  
pp. 561-564 ◽  
Author(s):  
Syed Humail Islam ◽  
Xuan Hui Qu ◽  
Farid Akhtar ◽  
Pei Zhong Feng ◽  
Xin Bo He
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Raw Materials ◽  
Solid Volume Fraction ◽  
Hydrogen Atmosphere ◽  
Microstructural Parameters ◽  
Heavy Alloys ◽  
Tungsten Heavy Alloys ◽  
Different Temperatures ◽  
Manufacturing Parameters

Mechanical properties of tungsten heavy alloys are dependent on many factors including the purity of the raw materials, their tungsten content, manufacturing parameters and the microstructure of the final compact. The main object of this research was to examine the effect of sintering conditions (temperature and time) on the microstructure of tungsten heavy alloys and how the resulting modification of the microstructure can be used to optimize their mechanical properties. Alloys composed of 88%, 93% and 95% wt. of tungsten with the balance of Ni: Fe in the ratio of 7:3 were consolidated into green compacts. Samples of each of the three resulting alloys were sintered at different temperatures (1350°C,1450°C and 1500 0C) for different sintering holding times (3 and 30 minutes) in hydrogen atmosphere. Standard metallographic procedures were used to obtain SEM micrographs. The mechanical properties of tungsten heavy alloys were found to be dependent on the microstructural parameters such as W particle size, solid volume fraction, connectivity and w-w contiguity. It was shown that the mechanical properties of the alloys, and especially their ductility, are harmed when tungsten grains are contiguous.

scholarly journals Effects of Sintering Conditions on Structures and Properties of Sintered Tungsten Heavy Alloy

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2338 ◽  
Author(s):  
Lenka Kunčická ◽  
Radim Kocich ◽  
Zuzana Klečková
Keyword(s):  
Sintering Temperature ◽  
Heavy Alloy ◽  
Tungsten Heavy Alloy ◽  
Fabrication Technology ◽  
Sintering Time ◽  
Heavy Alloys ◽  
Structures And Properties ◽  
Processing Step ◽  
Tungsten Heavy Alloys ◽  
Subsequent Quenching

Probably the most advantageous fabrication technology of tungsten heavy alloys enabling the achievement of required performance combines methods of powder metallurgy and processing by intensive plastic deformation. Since the selected processing conditions applied for each individual processing step affect the final structures and properties of the alloys, their optimization is of the utmost importance. This study deals with thorough investigations of the effects of sintering temperature, sintering time, and subsequent quenching in water on the structures and mechanical properties of a 93W6Ni1Co tungsten heavy alloy. The results showed that sintering at temperatures of or above 1525 °C leads to formation of structures featuring W agglomerates surrounded by the NiCo matrix. The sintering time has non-negligible effects on the microhardness of the sintered samples as it affects the diffusion and structure softening phenomena. Implementation of quenching to the processing technology results in excellent plasticity of the green sintered and quenched pieces of almost 20%, while maintaining the strength of more than 1000 MPa.

Effect of Sintering Conditions on the Phase Formation and Microstructure of Bi-2223/Ag/Ni Composite-Sheathed Tapes

2013 ◽  
Vol 745-746 ◽  
pp. 239-242
Author(s):  
Xing Pin Chen ◽  
Meng Liu ◽  
Xiao Wei Yu ◽  
Ming Ya Li
Keyword(s):  
Heat Treatment ◽  
Phase Formation ◽  
Microstructure Evolution ◽  
Significant Influence ◽  
Sintering Temperature ◽  
Secondary Phase ◽  
Secondary Phases ◽  
Different Temperatures ◽  
Sintering Conditions ◽  
Powder In Tube

Effect of sintering conditions in the first heat treatment on the phase and microstructure evolution of Bi-2223/Ag/Ni composite-sheathed tapes fabricated by powder-in-tube method was studied. Samples were sintered at different temperatures for different time in an atmosphere of 14.5% O2. The results showed that this higher O2 atmosphere improved the content of Bi-2223 phase. XRD and SEM results showed that Bi-2223 content increased with the extension of the dwelling time. Meanwhile, the sintering temperature had significant influence on the Bi-2223 content and secondary phase dimensions as well. With the increase of the sintering temperature, the Bi-2223 content reached to a maximum at 834. With further increase of sintering temperature, the Bi-2223 phase was decomposed to Bi-2212 and others secondary phases.

scholarly journals Investigation of tungsten heavy alloys using powder metallurgy technique

2021 ◽  
Vol 13 (2) ◽  
pp. 130-136
Author(s):  
Arafa S. Sobha ◽  
◽  
Amr Adela ◽  
Abdelhay Mohameda ◽  
Ali Abd El-Atya ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Process Control ◽  
Sintering Temperature ◽  
Control Agent ◽  
Preparation Condition ◽  
Electrical Contacts ◽  
Nano Particle ◽  
Process Control Agent ◽  
Heavy Alloys ◽  
Tungsten Heavy Alloys

Recently, developing new alloys of Tungsten heavy (WHA) is the most important issue that researchers considered due to their wide applications of radiation protectors, vibration absorber, kinetic energy penetrators and heavy-duty electrical contacts. The present work shows 9 different Tungsten alloys with a variety of weight percent’s from "Graphene" as a Nano- particle additive. The proposed alloys produced by minimizing manufacturing parameters by applying the Taguchi technique. In addition, this work used to relate the Powder-Metallurgy (PM) parameters such as Sintering Temperature (ST) level, the weight % of the added Nano-particle of Graphene (Gw) and the type of Process Control Agent (PCA) with the mechanical characteristics such as Young’s modulus, modulus of Bulk, modulus of Shear, Poisson's number, Vickers hardness, Grain size , Relative Density. The results showed that specimen number 8 is given higher values of modulus of elasticity, reached 326.2 GPa, bulk value of 255.64 GPa, and shear value of 126.7 GPa with PM preparation condition at 15000C sintering temperature, stearic acid as a process control agent (PCA) and 0.0 %Wt. of Graphene.

scholarly journals Microwave sintering of tungsten heavy alloys

2018 ◽  
Vol 16 (2) ◽  
Author(s):  
G. Prabhu ◽  
M. Sankaranarayana ◽  
T. K. Nandy
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Microwave Sintering ◽  
Microstructural Parameters ◽  
Heavy Alloys ◽  
Tungsten Heavy Alloys ◽  
Conventional Sintering ◽  
Superior Mechanical Properties ◽  
High Tungsten Content ◽  
Full Densification

To understand microwave sintering of heavy alloys with high tungsten content, 93W-4.9Ni-2.1Fe alloy was sintered using a 6 kW, 2.45 GHz microwave sintering furnace at 1783 K (1510˚ºC) and 1793 K (1520˚ºC). The alloy sintered at 1793 K (1520˚ºC) achieved full densification and had improved microstructural features, superior mechanical properties compared to 99.4% densification and relatively inferior properties obtained in the alloy sintered at 1783 K (1510˚ºC). This study also includes a comparison between microwave sintered and conventionally sintered 93W-4.9Ni-2.1Fe alloy (sintered at 1793K (1520ºC)). Contrary to the full densification and superior mechanical properties obtained in microwave sintering, conventional sintering at 1793K (1520ºC) resulted in only 99.6% densification and substantially inferior properties. Analyses of microstructure and fracture surface revealed that key microstructural parameters such as tungsten grain size, tungsten-tungsten contiguity, matrix volume fraction and also the fracture mode were significantly different between the alloys processed by the two routes. Possible reasons behind dissimilar densification, significantly different microstructures and mechanical properties obtained between these two modes of sintering, are also discussed in this study.

Effect of alloying addition and microstructural parameters on mechanical properties of 93% tungsten heavy alloys

2015 ◽  
Vol 640 ◽  
pp. 82-90 ◽  
Author(s):  
U. Ravi Kiran ◽  
A. Panchal ◽  
M. Sankaranarayana ◽  
G.V.S. Nageswara Rao ◽  
T.K. Nandy
Keyword(s):  
Mechanical Properties ◽  
Microstructural Parameters ◽  
Heavy Alloys ◽  
Tungsten Heavy Alloys ◽  
Effect Of Alloying
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