Effect of grain size on the strength of deformed 36NKhTYu alloy aged by a discontinuous mechanism of ??-phase precipitation

1977 ◽  
Vol 20 (9) ◽  
pp. 1163-1166
Author(s):  
V. F. Sukhovarov ◽  
R. D. Strokatov ◽  
Yu. V. Svitich
Keyword(s):  
Grain Size ◽  
Phase Precipitation ◽  
36Nkhtyu Alloy

Creep Cavitation Enhanced by Glass Pocket Formation in a Tetragonal Zirconia Doped with 0.3 WT% Pure Silica

1998 ◽  
Vol 539 ◽  
Author(s):  
K. Morita ◽  
K. Hiraga ◽  
Y. Sakka
Keyword(s):  
Grain Size ◽  
Glass Phase ◽  
Tetragonal Zirconia ◽  
Constant Stress ◽  
Cavity Formation ◽  
Phase Precipitation ◽  
Pure Silica ◽  
Creep Cavitation ◽  
Pocket Formation ◽  
The Relationship

AbstractThe relationship between intergranular microstructures and cavitation is examined in a yttria-stabilized tetragonal zirconia doped with 0.2-0.4 wt% SiO2 under constant stress loading in tension. An increase in the initial grain size for a constant SiO2-addition or an increase in SiO2-addition for a constant grain size enhances the precipitation of a glass phase at the multiple grain junctions during deformation. Simultaneously with the enhanced glass phase precipitation, intergranular cavitation is also enhanced. This is because the precipitated glass phase act as the site of cavity formation.

Effects of Rare Earth on Microstructure and Mechanical Properties of Al-3.2Mg Alloy

2015 ◽  
Vol 817 ◽  
pp. 192-197
Author(s):  
Xin Zhang ◽  
Ze Hua Wang ◽  
Ze Hua Zhou ◽  
Jian Ming Xu ◽  
Zhao Jun Zhong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Tensile Strength ◽  
Rare Earth ◽  
Second Phase ◽  
Phase Precipitation ◽  
X Ray ◽  
Scanning Electron

A series of Al-3.2Mg alloys with addition of 0~1.6 wt.% rare earth (Ce and La) were prepared. The microstructure of as-cast Al-3.2Mg alloys was investigated by optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and the tensile strength was measured. The results indicated that the addition of rare earth elements refined grain size and secondary dendrite arm spacing (SDAS), and the tensile strength was affected by means of the second-phase precipitation and the grain boundary. Accordingly, the ductility of Al-3.2Mg alloys reduced with the increasing of RE addition due to the more second-phase formation.

Influence of the grain size on deleterious phase precipitation in superduplex stainless steel UNS S32750

2009 ◽  
Vol 60 (3) ◽  
pp. 165-172 ◽  
Author(s):  
J.M. Pardal ◽  
S.S.M. Tavares ◽  
M. Cindra Fonseca ◽  
J.A. de Souza ◽  
R.R.A. Côrte ◽  
...  
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Phase Precipitation ◽  
Superduplex Stainless Steel

Grain growth in nanocomposite Ti–B–N films during deposition: The effect of amorphous phase precipitation

2006 ◽  
Vol 21 (1) ◽  
pp. 82-87 ◽  
Author(s):  
Z-J. Liu ◽  
Y.H. Lu ◽  
Y.G. Shen
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Grain Growth ◽  
Amorphous Phase ◽  
Amorphous Materials ◽  
Film Deposition ◽  
Growth Exponent ◽  
Experimental Investigations ◽  
Phase Precipitation ◽  
X Ray

Experimental investigations by high-resolution transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction show that during sputter-deposition of Ti–B–N films amorphous materials, e.g., TiB2 and BN, are found to precipitate at the grain boundaries, resulting in a decrease in grain size when the boron concentration or the amount of amorphous phase increases. To understand these experimental observations, we have used Monte Carlo simulations to investigate the effect of the amorphous phase precipitation on grain growth during film deposition. Our simulations demonstrate that the precipitation of amorphous phase at the grain boundaries can lower the grain growth exponent and thus leads to a low grain growth rate, particularly in the case of large amounts of amorphous phase. As a result, an exponential decay in grain size with the amount of amorphous phase can be observed in our simulations, which is in reasonably good agreement with the experimental results.

Microstructural Kinetics in Alloys Undergoing Transmutations: Application to Aic Neutron Absorbers

1996 ◽  
Vol 439 ◽  
Author(s):  
C. Desgranges ◽  
G. Martin ◽  
F. Defoort
Keyword(s):  
Grain Size ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Second Phase ◽  
Phase Precipitation ◽  
Water Reactors ◽  
Two Phases ◽  
Control Rods ◽  
Kinetics Of

AbstractWhenever an alloy changes composition because of metal to metal transmutations, as is the case in Ag-In-Cd alloys undergoing (n, −) actions in the control rods of Pressurised Water Reactors, unique features may develop.A simple model shows that in a two components alloy more than two phases can coexist under appropriate irradiation conditions i.e. temperature, which scales diffusivities and solubilities, and flux, which scales the transmutations rate; because second phase precipitation occurs at the grain boundaries, the grain size in the underlying matrix is found to be one important parameter of the process.The above ideas are illustrated on a multicomponent alloy, the thermodynamics and the kinetics of which are treated at the same level of sophistication in a mean field approximation.

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.

The Nature of Delta Phase Precipitation in Inconel 718

1982 ◽  
Vol 40 ◽  
pp. 724-725
Author(s):  
L. S. Lin ◽  
C. C. Law
Keyword(s):  
Inconel 718 ◽  
Base Alloy ◽  
High Strength ◽  
Physical Metallurgy ◽  
Nickel Base Alloy ◽  
Phase Precipitation ◽  
Weight Percentage ◽  
Delta Phase ◽  
The Subject ◽  
Nickel Base

Inconel 718, a precipitation hardenable nickel-base alloy, is a versatile high strength, weldable wrought alloy that is used in the gas turbine industry for components operated at temperatures up to about 1300°F. The nominal chemical composition is 0.6A1-0.9Ti-19.OCr-18.0Fe-3Mo-5.2(Cb + Ta)- 0.1C with the balance Ni (in weight percentage). The physical metallurgy of IN 718 has been the subject of a number of investigations and it is now established that hardening is due, primarily, to the formation of metastable, disc-shaped γ" an ordered body-centered tetragonal structure (DO2 2 type superlattice).

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.

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