scholarly journals Effect of Grain Size on Rotary swaging of Sintered Tungsten Rod

2021 ◽  
Author(s):  
Shaoxin Zhou ◽  
Jiancan Yang ◽  
Yingchao Zhang ◽  
Peng Zhang ◽  
Zuoren Nie
Keyword(s):  
Grain Size ◽  
Rotary Swaging ◽  
Sintered Tungsten

Grain Size Modification by Micro Rotary Swaging

2015 ◽  
Vol 651-653 ◽  
pp. 627-632 ◽  
Author(s):  
Svetlana Ishkina ◽  
Bernd Kuhfuss ◽  
Christian Schenck
Keyword(s):  
Grain Size ◽  
Longitudinal Section ◽  
Forming Process ◽  
Boundary Area ◽  
Cold Forming ◽  
Flat Surfaces ◽  
Rotary Swaging ◽  
2D Simulation ◽  
Physical Tests ◽  
Formed Part

Rotary swaging is a well established cold forming process e.g. in the automotive industry. In order to modify the material properties by swaging systematically, a new process of swaging with asymmetrical strokes of the forming dies is investigated. The newly developed tools feature flat surfaces and do not represent the geometry of the formed part as in conventional swaging. Numerical simulation and physical tests are carried out with special regard to the resulting geometry, mechanical properties and the microstructure. During these tests copper wires with diameter d0=1 mm are formed. Regarding the microstructure in the longitudinal section of formed specimens, elongation of grains in the central part and grain size reduction in the boundary area are observed. Furthermore, this approach opens up new possibilities to configure the geometry of wires. 2D-simulation is applied and discussed in the paper to investigate change of the processed geometry (cross-section) and shear strain distribution during the rotary swaging process.

Influence of Material Composition on Ductile Machining of Tungsten Carbide in Elliptical Vibration Cutting

2012 ◽  
Vol 523-524 ◽  
pp. 113-118 ◽  
Author(s):  
Jian Guo Zhang ◽  
Norikazu Suzuki ◽  
Takashi Kato ◽  
Rei Hino ◽  
Eiji Shamoto
Keyword(s):  
Grain Size ◽  
Tungsten Carbide ◽  
Material Composition ◽  
Elliptical Vibration Cutting ◽  
Vibration Cutting ◽  
Elliptical Vibration ◽  
Sintered Tungsten ◽  
Ductile Machining ◽  
Binder Material ◽  
Ultrasonic Elliptical Vibration

Tungsten carbide is a crucial material for glass molding in optical industry. The present study investigated a feasibility of ductile machining of sintered tungsten carbide for glass molding by applying ultrasonic elliptical vibration cutting technology with single crystal diamond tool. Grain size and binder material of sintered tungsten carbide have an influence on hardness and/or toughness of the material. Binder material also has a chemical affinity to diamond. In order to examine the influence of material composition on ductile machining of tungsten carbide, a series of grooving and planing experiments were conducted to several different tungsten carbide workpieces with the different binder phase and the different grain size. The experimental results indicated that micro grooving in a ductile mode can be attained successfully by applying ultrasonic elliptical vibration cutting, while finished surface deteriorates with brittle fractures in ordinary cutting. It was also clarified that grain size and binder material have significant influence on the deteriorations in the surface quality, the tool shape and the cutting forces.

Machinability of CBN Tool in Turning of Tungsten Carbide

2012 ◽  
Vol 523-524 ◽  
pp. 70-75 ◽  
Author(s):  
Seji Tsurimoto ◽  
Toshimichi Moriwaki ◽  
Masafumi Nagata
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Tool Wear ◽  
Tungsten Carbide ◽  
Cutting Speed ◽  
High Hardness ◽  
Cbn Tool ◽  
Sintered Tungsten ◽  
Mean Grain Size ◽  
Near Future

Tungsten Carbide have extremely high hardness and wear-resistivity compared with conventional steel materials, and it is expected that the Tungsten carbide can be applied widely to dies and molds in the near future. In order to develop an efficient machining method of Tungsten Carbide for the dies and molds, series of cutting experiments were carried out to turn the sintered Tungsten Carbide materials with CBN tool. The selected sintered Tungsten Carbide workpieces are those containing Tungsten Carbide grains with mean grain size of 5μm, and 15wt%, 20wt% and 22wt% of Cobalt binder. The sintered CBN tool selected contains super-fine grains of CBN with mean grain size of 1μm. The cutting speed was varied from 10m/min to 60m/min, and the tool wear and the surface roughness were measured. It is concluded that the tool wear is less when cutting the sintered Tungsten Carbide containing larger amount of Cobalt binder. The surface roughness of about 2μm in Rz is obtained.

scholarly journals Enhanced Fatigue Strength of Commercially Pure Ti Processed by Rotary Swaging

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Hasan ALkhazraji ◽  
Ehab El-Danaf ◽  
Manfred Wollmann ◽  
Lothar Wagner
Keyword(s):  
Grain Size ◽  
Fatigue Strength ◽  
Crack Growth ◽  
Slip Length ◽  
Pure Titanium ◽  
Fatigue Tests ◽  
Recrystallization Temperature ◽  
Commercially Pure Titanium ◽  
Rotary Swaging ◽  
Commercially Pure

Fully reversed bending fatigue tests were performed on polished hour-glass specimens of commercially pure titanium grade 1 with three different grain sizes, that were produced by severe plastic deformation (rotary swaging) and subheat treatments, in order to examine the effect of grain size on fatigue. An improvement in fatigue strength was observed, as the polycrystal grain size was refined. The endurance limit stress was shown to depend on the inverse square root of the grain size as described empirically by a type of Hall-Petch relation. The effect of refining grain size on fatigue crack growth is to increase the number of microstructural barriers to the advancing crack and to reduce the slip length ahead of the crack tip, and thereby lower the crack growth rate. It was found that postdeformation annealing above recrystallization temperature could additionally enhance the work-hardening capability and the ductility of the swaged material, which led to a marked reduction in the fatigue notch sensitivity. At the same time, this reduction was accompanied with a pronounced loss in strength. The high cycle fatigue performance was discussed in detail based on microstructure and mechanical properties.

Effect of Shock Loading on the Microstructure of Uniloy 326

1974 ◽  
Vol 32 ◽  
pp. 504-505
Author(s):  
K. P. Staudhammer ◽  
L. E. Murr
Keyword(s):  
Grain Size ◽  
Shock Loading ◽  
Current Investigation ◽  
Two Phase ◽  
05 C ◽  
Shock Deformation ◽  
Heat Treated

The effect of shock loading on a variety of steels has been reviewed recently by Leslie. It is generally observed that significant changes in microstructure and microhardness are produced by explosive shock deformation. While the effect of shock loading on austenitic, ferritic, martensitic, and pearlitic structures has been investigated, there have been no systematic studies of the shock-loading of microduplex structures.In the current investigation, the shock-loading response of millrolled and heat-treated Uniloy 326 (thickness 60 mil) having a residual grain size of 1 to 2μ before shock loading was studied. Uniloy 326 is a two phase (microduplex) alloy consisting of 30% austenite (γ) in a ferrite (α) matrix; with the composition.3% Ti, 1% Mn, .6% Si,.05% C, 6% Ni, 26% Cr, balance Fe.

Aspects of microanalysis in a transmission electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 510-511
Author(s):  
R. Sinclair ◽  
B.E. Jacobson
Keyword(s):  
Grain Size ◽  
Electron Beam ◽  
Electron Microscope ◽  
Chemical Analysis ◽  
Transmission Electron Microscope ◽  
Vapor Deposition ◽  
Critical Currents ◽  
X Ray ◽  
Fine Grain ◽  
Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

Novel magneto-optical recording materials: Bi-substituted garnet films

1991 ◽  
Vol 49 ◽  
pp. 776-777
Author(s):  
Takao Suzuki ◽  
Hossein Nuri
Keyword(s):  
Grain Size ◽  
Amorphous Film ◽  
Nitrogen Atmosphere ◽  
Optical Recording ◽  
Garnet Film ◽  
Media Noise ◽  
Garnet Films ◽  
Order Of Magnitude ◽  
A New Technique ◽  
A Current

For future high density magneto-optical recording materials, a Bi-substituted garnet film ((BiDy)3(FeGa)5O12) is an attractive candidate since it has strong magneto-optic effect at short wavelengths less than 600 nm. The signal in read back performance at 500 nm using a garnet film can be an order of magnitude higher than a current rare earth-transition metal amorphous film. However, the granularity and surface roughness of such crystalline garnet films are the key to control for minimizing media noise.We have demonstrated a new technique to fabricate a garnet film which has much smaller grain size and smoother surfaces than those annealed in a conventional oven. This method employs a high ramp-up rate annealing (Γ = 50 ~ 100 C/s) in nitrogen atmosphere. Fig.1 shows a typical microstruture of a Bi-susbtituted garnet film deposited by r.f. sputtering and then subsequently crystallized by a rapid thermal annealing technique at Γ = 50 C/s at 650 °C for 2 min. The structure is a single phase of garnet, and a grain size is about 300A.

Structure of second phases in TiAl alloys containing Cr and B

1991 ◽  
Vol 49 ◽  
pp. 576-577
Author(s):  
Ernest L. Hall ◽  
Shyh-Chin Huang
Keyword(s):  
Grain Size ◽  
Second Phase ◽  
Structure And Properties ◽  
Tial Alloys ◽  
Second Phases ◽  
Interstitial Elements

Addition of interstitial elements to γ-TiAl alloys is currently being explored as a method for improving the properties of these alloys. Previous work in which a number of interstitial elements were studied showed that boron was particularly effective in refining the grain size in castings, and led to enhanced strength while maintaining reasonable ductility. Other investigators have shown that B in γ-TiAl alloys tends to promote the formation of TiB2 as a second phase. In this study, the microstructure of Bcontaining TiAl alloys was examined in detail in order to describe the mechanism by which B alters the structure and properties of these alloys.

Interfacial studies in Nb3Sn superconductors

1991 ◽  
Vol 49 ◽  
pp. 590-591
Author(s):  
Ernest L. Hall ◽  
Lee E. Rumaner ◽  
Mark G. Benz
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Flux Pinning ◽  
Size Control ◽  
High Magnetic Fields ◽  
Type Ii ◽  
Reaction Interface ◽  
Liquid Diffusion ◽  
Type Ii Superconductor ◽  
Grain Size Control

The intermetallic compound Nb3Sn is a type-II superconductor of interest because it has high values of critical current density Jc in high magnetic fields. One method of forming this compound involves diffusion of Sn into Nb foil containing small amounts of Zr and O. In order to maintain high values of Jc, it is important to keep the grain size in the Nb3Sn as small as possible, since the grain boundaries act as flux-pinning sites. It has been known for many years that Zr and O were essential to grain size control in this process. In previous work, we have shown that (a) the Sn is transported to the Nb3Sn/Nb interface by liquid diffusion along grain boundaries; (b) the Zr and O form small ZrO2 particles in the Nb3Sn grains; and (c) many very small Nb3Sn grains nucleate from a single Nb grain at the reaction interface. In this paper we report the results of detailed studies of the Nb3Sn/Nb3Sn, Nb3Sn/Nb, and Nb3Sn/ZrO2 interfaces.

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