Grain Size Distribution Effect on Mechanical Behavior of Nanocrystalline Materials

2004 ◽  
Vol 821 ◽  
Author(s):  
A.V. Sergueeva ◽  
N.A. Mara ◽  
A.K. Mukherjee
Keyword(s):  
Grain Size ◽  
Mechanical Behavior ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Nanocrystalline Materials ◽  
Tensile Deformation ◽  
Size Structure ◽  
Niti Alloy ◽  
Distribution Effect ◽  
The Matrix

AbstractGrain size distribution effect on the mechanical behavior of NiTi and Vitroperm alloys were investigated. Yielding at significantly lower stresses than found in equiaxed counterparts, along with well defined strain hardening was observed in these nanocrystalline materials with large grains embedded in the matrix during tensile deformation at temperatures of 0.4Tm. At higher temperature the effect of grain size distribution on yield stress was not revealed while plasticity was increased in 50% in NiTi alloy with bimodal grain size structure.

Color in ceramic glazes: Analysis of pigment and opacifier grain size distribution effect by spectrophotometer

2008 ◽  
Vol 28 (9) ◽  
pp. 1777-1781 ◽  
Author(s):  
L.M. Schabbach ◽  
F. Bondioli ◽  
A.M. Ferrari ◽  
T. Manfredini ◽  
C.O. Petter ◽  
...  
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Distribution Effect

Effect of Vibrating Load on Grain Size Distribution of Crushed Rock Layer

2010 ◽  
Vol 168-170 ◽  
pp. 663-668
Author(s):  
Li Jun Yang ◽  
Wen Hui Bai ◽  
Bin Xiang Sun ◽  
Shuang Jie Wang ◽  
Jin Zhao Zhang
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Crushed Rock ◽  
Rock Layer ◽  
Fines Content ◽  
The Matrix ◽  
Study Laboratory ◽  
Permafrost Regions ◽  
Highway Embankment

For the construction of the proposed Qinghai-Tibet Express Highway in warm and ice-rich permafrost regions, it will be necessary to utilize the new technique of cooling the ground temperature by the coarsely crushed rock layer with a low fines content, instead of the traditional measures taken to increase simply thermal resistances, so as to protect from damage to highway embankment due to thaw settlement. The vibrating loads such as wheel load and tamping load may cause the breakage and abrasion of the matrix grains in the coarsely crushed rock layer. This results in decreasing of grain size and increasing of fines content in the crushed rock layer, thus decreasing the porosity of crushed rock layer. The smaller porosity of crushed rock layer may weaken the cooling effect of buoyancy-driven natural convection of the pore air in the crushed rock layer of the highway embankment, thus resulting in instability and failure of the embankment structure in permafrost regions. Under these conditions, the influence of vibrating load on the grain size distribution of the coarsely crushed rock layer has to be investigated experimentally. In the present study, laboratory experiments on the grain size variation of the coarsely crushed rock layer under vertically vibrating loads were carried out. The test results show that the vibrating load can cause the breakage and abrasion of the matrix grains in the coarsely crushed rock layer and the shapes of coarely crushed rock grain tend to be non-angular.

The Inverse Hall-Petch Effect—Fact or Artifact?

2000 ◽  
Vol 634 ◽  
Author(s):  
Carl C. Koch ◽  
J. Narayan
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Computer Simulations ◽  
Nanocrystalline Materials ◽  
Grain Sizes ◽  
Average Grain Size

ABSTRACTThis paper critically reviews the data in the literature which gives softening—the inverse Hall-Petch effect—at the finest nanoscale grain sizes. The difficulties with obtaining artifactfree samples of nanocrystalline materials will be discussed along with the problems of measurement of the average grain size distribution. Computer simulations which predict the inverse Hall-Petch effect are also noted as well as the models which have been proposed for the effect. It is concluded that while only a few of the experiments which have reported the inverse Hall-Petch effect are free from obvious or possible artifacts, these few along with the predictions of computer simulations suggest it is real. However, it seems that it should only be observed for grain sizes less than about 10 nm.

Homogeneous fabrication and densification of zirconia-toughened alumina (ZTA) composite by the surface-induced coating

1990 ◽  
Vol 5 (3) ◽  
pp. 615-622 ◽  
Author(s):  
Hyun M. Jang ◽  
Jong H. Moon
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Ionic Species ◽  
Colloidal Dispersion ◽  
Solution Interface ◽  
The Matrix ◽  
Electrochemical Phenomena ◽  
Selective Formation ◽  
Highly Uniform

This article proposes a new scheme for fabricating homogeneous Al2O3–ZrO2 composite, in which a thermodynamic theory of interfacial electrochemical phenomena is applied. The theory predicts that a heterogeneous Al2O3 interface in colloidal dispersion can induce an enhanced concentration of the ionic species needed for a selective formation of the ZrO2 precursor at the Al2O3/aqueous solution interface. Based on this proposition, a homogeneous Al2O3–ZrO2 composite powder was fabricated by a surface-induced coating of the fine ZrO2 precursor on the kinetically stable colloid particles of Al2O3. The composite prepared by the surface-induced coating was characterized by a uniform spatial distribution of the dispersed ZrO2 phase and by the absence of large ZrO2 grains formed from hard ZrO2 agglomerates. The composite also showed highly uniform grain size distribution of both the dispersed ZrO2 and the matrix Al2O3 phases. The uniform grain size distribution of the matrix phase indicates that the homogeneous coating of the fine ZrO2 particles is effectively pinning the Al2O3 grain boundaries.

scholarly journals Influence of grain size distribution on the mechanical behavior of light alloys in wide range of strain rates

2017 ◽  
Author(s):  
Vladimir A. Skripnyak ◽  
Natalia V. Skripnyak ◽  
Evgeniya G. Skripnyak ◽  
Vladimir V. Skripnyak
Keyword(s):  
Grain Size ◽  
Mechanical Behavior ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Strain Rates ◽  
Light Alloys ◽  
Wide Range
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