scholarly journals Influence of the Matrix Grain Size on the Apparent Density and Bending Strength of Sand Cores

2017 ◽  
Vol 17 (1) ◽  
pp. 27-30
Author(s):  
R. Dańko
Keyword(s):  
Grain Size ◽  
Apparent Density ◽  
Bending Strength ◽  
Diffraction Method ◽  
Laser Diffraction ◽  
Grain Sizes ◽  
The Matrix

Abstract The results of investigations of the influence of the matrix grain sizes on properties of cores made by the blowing method are presented in the hereby paper. Five kinds of matrices, differing in grain size compositions, determined by the laser diffraction method in the Analysette 22NanoTec device, were applied in investigations. Individual kinds of matrices were used for making core sands in the Cordis technology. From these sands the shaped elements, for determining the apparent density of compacted sands and their bending strength, were made by the blowing method. The shaped elements (cores) were made at shooting pressures being 3, 4 and 5 atn. The bending strength of samples were determined directly after their preparation and after the storing time of 1 hour.

Microstructure and Bending Property of Welding Joint Prepared by 5356 Welding Wire Added Sc, Zr and Er

2014 ◽  
Vol 941-944 ◽  
pp. 2003-2006
Author(s):  
Xiao Ming Wang ◽  
Sheng Zhu ◽  
Zhi Hao Zhao ◽  
Qi Wei Wang ◽  
Xi Hua Peng
Keyword(s):  
Grain Size ◽  
Bending Strength ◽  
Optical Microscope ◽  
Welding Wire ◽  
Welding Zone ◽  
Welding Joint ◽  
Bending Property ◽  
7A52 Aluminum Alloy ◽  
The Matrix ◽  
New Type

7A52 aluminum alloy was welded by using 5356 welding wire added Sc, Zr and Er. Microstructure of the welding joint was observed by using optical microscope (OM). Bending property was tested by bending tester. The results demonstrated that, compared to employ traditional 5356 welding wire, the grains in welding zone (WZ) were much finer; The grains in fused zone (FZ) nucleated and grew from the matrix; The grain size along heat affected zone (HAZ) dercearsed gradually.The welding joint prepared by using 5356 welding wire added single 0.3%Sc possessed maxium face bending strength. The welding joint fabricated by using 5356 welding wire added compond 0.1%Sc+0.2% Er possessed maxium rear bending strength. The fine isometric crystal and isometric dendrite generated at the welding zone when the new type 5356 wire added gingle Sc or compound Sc+Er was employed, which make the welding joint represent excellent bending property, respectively.

scholarly journals Comparison of Pipette and Laser Diffraction Methods in Determining the Granulometric Content of Fluvial Sediment Samples

2013 ◽  
Vol 6 (3-4) ◽  
pp. 49-54 ◽  
Author(s):  
Ágnes Kun ◽  
Orsolya Katona ◽  
György Sipos ◽  
Károly Barta
Keyword(s):  
Grain Size ◽  
Size Range ◽  
Accurate Determination ◽  
Diffraction Method ◽  
Laser Diffraction ◽  
Detailed Data ◽  
Fluvial Sediment ◽  
Sediment Samples ◽  
Correlation Factors

Abstract Nowadays there is a growing demand for rapid and accurate determination of grain size distribution. The conventional pipette method is time-consuming and provides less detailed data compared to recently introduced methods. However, in Hungarian practice the pipette method is still considered to be the standard one, as there are a long series of measurements, and grain size thresholds used in sedimentology and soil sciences are based on this approach. The aim of our research was to determine the comparability of the laser diffraction method (LDM) with the conventional pipette method (PM), in order to investigate the controversial question on the interchangeability of the two methods. Based on our measurements on some representative fluvial sediment samples, we found that the largest difference in results can be expected in the silty grain size range. However if the main fractions (clay, silt, sand) are considered the methods provided similar very results, and correlation factors were above 0.92. In all, the LDM has a clear advantage because of its speed, reproducibility and fewer possibilities for operator failure.

scholarly journals Comparison of laser diffraction method and hydrometer method for soil particle size distribution analysis

2021 ◽  
Vol 24 (1) ◽  
pp. 49-55
Author(s):  
Kateřina Sedláčková ◽  
Lenka Ševelová
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Distribution Curve ◽  
Diffraction Method ◽  
Laser Diffraction ◽  
Soil Science ◽  
Distribution Analysis

Abstract The article aims to present a comparative study of two methods used to determine the particle size distribution of fine and medium coarse soils. These methods are used to determine the grain size distribution curve in practice; however, for different purposes. The classical sedimentation method, based on the Stoke’s sedimentation law (hydrometer, areometric, the Casagrande’s method), standardized for a geotechnical classification of soils was compared with the laser diffraction method on the Mastersizer 3,000 analyser used for soil science purposes. The first comparison on nine samples showed significant differences, especially for larger fractions above 0.01 mm. All measured values of falls from laser diffraction analysis (LDA) showed higher values of all analysed fractions. It was also interesting to follow the trend between the tests for the preparation of conversion factors. The analysis also outlined the direction for further comparison. For the geotechnical use of the LDA, it will be necessary to take into account the sample preparation and processing before analysis.

1200 to 1400 K slow strain rate compressive behavior of small grain size NiAl/Ni2AlTi alloys and NiAl/Ni2AlTi–TiB2 composites

1989 ◽  
Vol 4 (5) ◽  
pp. 1164-1171 ◽  
Author(s):  
J. Daniel Whittenberger ◽  
R. K. Viswanadham ◽  
S. K. Mannan ◽  
K. S. Kumar
Keyword(s):  
Grain Size ◽  
Elevated Temperature ◽  
Matrix Material ◽  
Matrix Composition ◽  
Strain Rates ◽  
Transverse Cracks ◽  
State Behavior ◽  
Strain Behavior ◽  
Grain Sizes ◽  
The Matrix

Since 1976 NiAl–Ni2AlTi alloys have been known to possess elevated temperature mechanical properties approaching those of Ni-base superalloys; however, due to their apparent brittleness, little additional work has been undertaken to exploit this strength. In an attempt to instill ductility in these materials, small grain size single (Ni–45Al–5Ti) and two (Ni–40Al–10Ti) phase intermetallics were fabricated by XDTM technology and tested (XDTM is a trademark of Martin Marietta Corporation). As these compositions have the potential for being the matrix material in high temperature composites, Ni–40Al–10Ti and Ni–45Al–5Ti with 20 vol.% TiB2 in the form of ∼1 μm diameter particles were also investigated. The as-fabricated materials were fully dense and polycrystalline. The grain sizes measured ∼8 μm for Ti-poor and about 15 μm for the Ti-rich unreinforced materials but could not be determined for either TiB2 containing composite. Elevated temperature compression testing was conducted to about 8% deformation between 1200 and 1400 K with strain rates varying from ∼10−4 to ∼10−7 s−1. The majority of the tests exhibited diffuse yielding over approximately 1% strain followed by negative strain hardening. However, a few experiments resulted in steady state behavior where deformation continued under a constant stress. The flow strengths on yielding of both forms of Ni–40Al–10Ti were higher than those for the Ni–45Al–5Ti versions. For each matrix composition the addition of 20 vol.% TiB2 decreased the strength at the higher strain rates in comparison to the TiB2-free forms. During slow deformation conditions, however, the particles do provide reinforcement. Light optical microscopy of tested specimens revealed that these materials are generally quite brittle as numerous longitudinal and transverse cracks were found irrespective of the type of stress-strain behavior.

The Effect of Grain Size and SiC Particulates on the Strength and Ductility of MoSi2

1993 ◽  
Vol 322 ◽  
Author(s):  
Amit K. Ghosh ◽  
Ajoy Basu
Keyword(s):  
Grain Size ◽  
Compression Behavior ◽  
Grain Sizes ◽  
Fine Grain ◽  
Compression Creep ◽  
The Matrix ◽  
Tension And Compression ◽  
Sic Particulates ◽  
Ductile To Brittle Transition ◽  
Strength And Ductility

AbstractMonolithic MoSi2 and MoSi2 reinforced with SiC particulate reinforcements have been produced with widely varying grain sizes. Monotonic compression behavior of these materials has been examined in the temperature range of room temperature to 1200°C. Based on these results, the ductile-to-brittle transition temperature at low deformation rate of MoSi2 and its composite appears to be near 900°C and may decrease slightly with decreasing grain size. Tension and compression creep behavior of these materials were also studied between 1100 and 1400°C. Creep strength of the matrix decreases with decreasing grain size even in the nominally dislocation climb-glide regime. While 20 vol% SiC particulates provide a reasonable amount of creep strengthening of the fine grain MoSi2 matrix, strengthening due to coarser grain size can be significantly higher in these materials. These results parallel those on other intermetallics.

scholarly journals Microstructure Evolution and Lifetime Extension Mechanism of Sn-Added Fe-Based Pre-Alloy Brazing Coating in Diamond Tools

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 364
Author(s):  
Dashuang Liu ◽  
Weimin Long ◽  
Mingfang Wu ◽  
Kai Qi ◽  
Juan Pu
Keyword(s):  
Grain Size ◽  
Flexural Strength ◽  
Microstructure Evolution ◽  
Hot Pressing ◽  
Alloy Powder ◽  
Bending Strength ◽  
Extension Mechanism ◽  
The Matrix ◽  
Hot Pressing Sintering ◽  
Lifetime Extension

The effect of Sn content added in pre-alloy powder on the microstructure, porosity, hardness and bending strength of hot pressing sintering of a diamond matrix was investigated. The results show that with the increase of Sn content in the pre-alloy powder, a reduction in grain size and porosity as well as an increase in hardness is observed. As a result of the reduction in porosity, the flexural strength increases with the increase in the Sn content in the pre-alloy powder. However, with the increase of Sn content, the bending strength decreases owing to the formation of Cu5.6Sn in the matrix. The properties of the diamond matrix are improved, and the lifetime of the diamond matrix is prolonged when the Sn content is 4 wt.%.

Measurement of WC Grain Size in Ultrafine Grained WC-Co Cemented Carbides

2013 ◽  
Vol 278-280 ◽  
pp. 460-463 ◽  
Author(s):  
Yi Gao Yuan ◽  
Xiao Xiao Zhang ◽  
Jian Jun Ding ◽  
Jun Ruan
Keyword(s):  
Grain Size ◽  
Diffraction Method ◽  
Cemented Carbides ◽  
Polished Surface ◽  
Grain Sizes ◽  
Ultrafine Grained ◽  
Average Grain Size ◽  
Measurement Results ◽  
Backscattered Electron ◽  
Imagej Software

Based on the backscattered electron (BSE) images and IMAGEJ image analysis software, the average grain size of WC in ultrafine grained WC-Co cemented carbides was measured. The result shows that BSE images of the polished surface not be etched are suitable for quantitative evaluating the grain size of WC in the ultrafine grained hardmetals. Both linear intercept method and equivalent circle diameter method can be used to accurately measure the grain sizes of WC in ultrafine grained hadmetals by using IMAGEJ software. Measurement results of WC grain sizes coincide with the conclusion of X-ray diffraction method

Mechanical Properties and Microstructure of Partially Sintered Zirconia Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1252-1254 ◽  
Author(s):  
Shi Bao Li ◽  
Zhao Hui Chen ◽  
Yi Min Zhao ◽  
Zhong Yi Wang ◽  
Li Hui Tang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Bending Strength ◽  
Target Material ◽  
Dental Restoration ◽  
Diameter Distribution ◽  
Zirconia Ceramics ◽  
Grain Sizes ◽  
Cad Cam

Partially sintered zirconia ceramics (PSZCs) for dental uses were prepared from zirconia nanopowder via isostatic pressing and partially sintering. The open porosities, pore diameters, grain sizes and mechanical properties of the ceramics with different densities were studied. The results show that the pores formed in the PSZCs are all open pores, with a diameter distribution of 60nm~130nm and a grain size distribution of 120~170nm. The machinability becomes worse when the density of PSZC is higher than 75% of the theoretical density, so a ceramic named PSZC-70% with density of 70%TD was selected as the target material. Its bending strength is 168 MPa and fracture toughness is 1.8 MPa·m1/2. A dental restoration framework can be obtained via machining the PSZC-70% on a dental CAD/CAM system.

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