scholarly journals Analytical Model to Calculate the Grain Size of Bulk Material Based on Its Electrical Resistance

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 21
Author(s):  
Thomas Mehner ◽  
Morgan Uland ◽  
Thomas Lampke

The electrical resistivity of a material can provide information on the microstructure. However, this is usually limited to thin layers. In this study, an analytical model is derived that correlates the measured electrical resistance with the average grain size of the material for different grain shapes and orientations. Rolled steel sheets (material: DC04) are microstructurally characterized by X-ray diffraction and optical microscopy. Their electrical resistivity is measured using the four-point probe method. The sheets are utilized to validate the model. An excellent agreement between the model predictions and the experimental data is achieved. By using a calibration, unknown grain sizes can be determined. The model is applicable for materials with monomodal grain-size distributions.

2012 ◽  
Vol 535-537 ◽  
pp. 593-596
Author(s):  
Zhi Fen Wang ◽  
Rong Dong Han ◽  
Shun Bing Zhou ◽  
Zhong Hai Yao ◽  
Li Xin Wu

Effect of annealing time on the microstructure and texture of IF steel sheets was investigated. Average grain size, grain boundary character and recrystallization texture were measured by X-ray diffraction (XRD) and electron backscatter diffraction (EBSD) in order to clarify the effect of annealing time on microstructure of recrystallization process. The average grain size increased with increasing annealing time. With rising annealing time, the number of low angle boundary (0~15o) decreased due to the mergence of grain with sub-boundary. The //ND (-fiber) pole intensity had a highest value annealed at 60s. The annealing time played an important role in recrystallization process which affected the mechanical properties and microstructure of IF steels.


2011 ◽  
Vol 299-300 ◽  
pp. 82-85
Author(s):  
Wei Liu ◽  
Qiong Hua Zhou

Nanocrystalline aluminium bulk material with average grain size of 25.2 nm was prepared by warm-vacuum-compaction method. The as-prepared nanocrystalline aluminium was characterized by X-ray diffraction (XRD), differential scanning calarmeutry analysis (DSC), thermogravimetric analysis (TG), and Microhardness test, respectively. The experimental results show that the average grain size and microstrain of the nanocrystalline aluminium are 25.2 nm and 0.018%, respectively. The melting point of as-prepared nanocrystalline aluminium is 918.9 K, which is lower than that of coarse-grained aluminium by 14 K. The endothermic value of nanocrystalline aluminium is 196.3J/g. The average microhardness of the as-prepared nanocrystalline aluminium is 1.65 GPa, which is 11 times higher than that of coarse-grained aluminium.


2011 ◽  
Vol 418-420 ◽  
pp. 726-730
Author(s):  
Yun Li Feng ◽  
Ming Cai ◽  
Li Bin Chen

It was analyzed by metallographic observation and X-ray diffraction method that the microstructure and texture in two kinds of Ti-IF steels, which produced by different hot rolling process,and it also was discussed that the formability and the texture in Ti-IF steels. The results showed that the microstructures of these two kinds of steels are Equiaxed ferrite grains, but the grain sizes are greatly different. Respectively the average grain size of steel A and B are 24.85μm and 11.85μm, and the average grain size number are 7.4 and 9.5. The {111} texture of steel B is stronger than A, besides, the deep drawing properties of steel B is better than A in the reason that disadvantaged texture{001} and {112} are not founded in steel B.


1989 ◽  
Vol 164 ◽  
Author(s):  
M.A. Hachicha ◽  
Etienne Bustarret

AbstractUndoped 500 nm-thick silicon layers with a crystalline fraction around 95% and an average grain size of 20 nm have been deposited at 350°C by 50 kHz triode PECVD in a H2/SiH4 mixture, in the presence of a magnetic field. Their room temperature (rt) dc conductivity μrt is 0.03 Δ−1cm−1 for a Hall mobility of 0.8 cm 2V−1s−1.The study by SIMS, infrared absorption, grazing angle x-ray diffraction and Raman scattering spectroscopies of the doped samples shows how the crystalline fraction and the grain size drop as the B2H6/SiH4 and PH3/SiH4 volumic ratios increase from 10 ppm to 1%.The rt dc conductivity reaches 2 Δ−1 cm−1 (Hall mobility: 15 cm2V−ls−1) for a solid phase density of 1019 cm−3 boron atoms, and 30 Δ−1cm−1 (Hall mobility: 55 cm2V−ls−1) at the maximum P incorporation of 8 × 1020cm−3.


Author(s):  
T. Pikula ◽  
T. Szumiata ◽  
K. Siedliska ◽  
V. I. Mitsiuk ◽  
R. Panek ◽  
...  

AbstractIn this work, BiFeO3 powders were synthesized by a sol–gel method. The influence of annealing temperature on the structure and magnetic properties of the samples has been discussed. X-ray diffraction studies showed that the purest phase was formed in the temperature range of 400 °C to 550 °C and the samples annealed at a temperature below 550 °C were of nanocrystalline character. Mössbauer spectroscopy and magnetization measurements were used as complementary methods to investigate the magnetic state of the samples. In particular, the appearance of weak ferromagnetic properties, significant growth of magnetization, and spin-glass-like behavior were observed along with the drop of average grain size. Mössbauer spectra were fitted by the model assuming cycloidal modulation of spins arrangement and properties of the spin cycloid were determined and analyzed. Most importantly, it was proved that the spin cycloid does not disappear even in the case of the samples with a particle size well below the cycloid modulation period λ = 62 nm. Furthermore, the cycloid becomes more anharmonic as the grain size decreases. The possible origination of weak ferromagnetism of the nanocrystalline samples has also been discussed.


2018 ◽  
Vol 283 ◽  
pp. 147-153 ◽  
Author(s):  
Supalak Manotham ◽  
Pichitchai Butnoi ◽  
Pharatree Jaita ◽  
Tawee Tunkasiri

In this work, the properties of lead-free 0.92(Bi0.5Na0.42K0.08)TiO3-0.08(BaNb0.01Ti0.99)O3 or 92BNKT-8BNbT ceramic has been investigated. The sample was fabricated by a solid-state reaction technique. The 92BNKT-8BNbT sample was well sintered and dense with high density value of 5.86 g/cm3. X-Ray diffraction (XRD) patterns showed a single perovskite phase with tetragonal symmetry and no impurity or secondary phases. The microstructure was analysed using a scanning electron microscopy (SEM). Average grain size was measured and calculated based on a mean linear intercept method. The ceramics had a cubic-like grain shape with an average grain size of 0.39 µm. The influence of temperature on the dielectric and ferroelectric properties of the ceramic was investigated. The dielectric curves exhibited broad transition peaks at Td and Tm, which were the characteristics of a diffuse phase transition. The polarization-electric field (P-E) hysteresis loop changed from well-saturated at room temperature (RT) to pinched-type loop at high temperature (HT) and the remanent polarization decreased from 21.25 µC/cm2 (at RT) to 5.96 µC/cm2 (at 150 °C).


Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2767 ◽  
Author(s):  
Chenchen Jiang ◽  
Qiuzhi Gao ◽  
Hailian Zhang ◽  
Ziyun Liu ◽  
Huijun Li

Microstructural evolutions of the 4Al alumina-forming austenitic steel after cold rolling with different reductions from 5% to 30% and then annealing were investigated using electron backscattering diffraction (EBSD), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Tensile properties and hardness were also measured. The results show that the average grain size gradually decreases with an increase in the cold-rolling reduction. The low angle grain boundaries (LAGBs) are dominant in the cold-rolled samples, but high angle grain boundaries (HAGBs) form in the annealed samples, indicating that the grains are refined under the action of dislocations. During cold rolling, high-density dislocations are initially introduced in the samples, which contributes to a large number of dislocations remaining after annealing. With the sustaining increase in cold-rolled deformation, the samples exhibit more excellent tensile strength and hardness due to the decrease in grain size and increase in dislocation density, especially for the samples subjected to 30% cold-rolling reduction. The contribution of dislocations on yield strength is more than 60%.


2007 ◽  
Vol 1056 ◽  
Author(s):  
Jafar F. Al-Sharab ◽  
Rajendra Sadangi ◽  
Vijay Shukla ◽  
Bernard Kear

ABSTRACTPolycrystalline Y2O3 is the material of choice for IR windows since it has excellent optical properties in the visible, and near infra-red band. However, current processing methods yield polycrystalline Y2O3 with large grain size (> 100 μm), which limits the hardness and erosion resistance attainable. One way to improve strength is to develop an ultra-fine grained material with acceptable optical transmission properties. To realize a fine-grained ceramic, one approach is to develop a composite structure, in which one phase inhibits the growth of the other phase during processing. In this study, Y2O3-MgO nanocomposite with various MgO content (20, 50 and 80 mol%) were synthesized using plasma spray method. Extensive characterization techniques including x-ray diffraction, scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Energy Dispersive spectrometry (EDS) were employed to study the synthesized powder as well as the consolidated sample. Transmission Electron Microscopy, as well as EDS chemical mapping, revealed that the consolidated sample have bi-continuous MgO-Y2O3 nanostructure with an average grain size of 200 nm.


2006 ◽  
Vol 530-531 ◽  
pp. 526-531 ◽  
Author(s):  
Claudinei dos Santos ◽  
L.H.P. Teixeira ◽  
J.K.M.F. Daguano ◽  
Kurt Strecker ◽  
Carlos Nelson Elias

In this work the influence of isothermal sintering time on the microstructural development of ZrO2-Al2O3 composite was studied. Powder mixture of ZrO2 containing 20 wt% Al2O3 was prepared by milling, compaction and sintering at 16000C, in air. The isothermal sintering time at 16000C was varied between 0 and 1440 min. The sintered samples were characterized in terms of phase composition and relative density. Their microstructures were characterized by grain size distributions and average grain size. These results were evaluated using the classic grain growth equation as a function of time, determining the grain growth exponent of these materials. Furthermore, the microstructural aspects were related to the mechanical properties (Vicker’s hardness and fracture toughness) of these composites.


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