Constituent Particles and Dispersoids in an Al-Mn-Fe-Si Alloy Studied in Three-Dimensions by Serial Sectioning

2013 ◽  
Vol 765 ◽  
pp. 451-455 ◽  
Author(s):  
Liam Dwyer ◽  
Joseph Robson ◽  
Joao Quinta da Fonseca ◽  
Nicolas Kamp ◽  
Teruo Hashimoto ◽  
...  
Keyword(s):  
Accurate Determination ◽  
Three Dimensions ◽  
Process Conditions ◽  
Second Phase ◽  
Serial Sectioning ◽  
3 Dimensional ◽  
Intermetallic Particles ◽  
Second Phase Particles ◽  
Proper Consideration

Second phase particles in wrought aluminium alloys are crucial in controlling recrystallization and texture. In Al-Mn-Fe-Si (3xxx) alloys, the size, spacing, and distribution of both large constituent particles and small dispersoids are manipulated by heat treatment to obtain the required final microstructure and texture for operations such as can-making. Understanding how these particles evolve as a function of process conditions is thus critical to optimize alloy performance. In this study, a novel 3-dimensional technique involving serial sectioning in the scanning electron microscope (SEM) has been used to analyse the intermetallic particles found in an as-cast and homogenized Al-Mn-Fe-Si alloy. This has allowed an accurate determination of the size and shape of the constituent particles and dispersoids derived from a 3-dimensional dataset. It is demonstrated that a proper consideration of the 3-dimensional microstructure reveals important features that are not obvious from 2-dimensional sections alone.

Polishing process effect on the image of dispersed precipitates

1984 ◽  
Vol 42 ◽  
pp. 534-535
Author(s):  
C.T. Hu ◽  
C.W. Allen
Keyword(s):  
Matrix Material ◽  
Specimen Preparation ◽  
Second Phase ◽  
Precipitate Particle ◽  
Polishing Process ◽  
Second Phase Particles ◽  
The Matrix ◽  
Surface Profiles ◽  
Thinning Process

One important problem in determination of precipitate particle size is the effect of preferential thinning during TEM specimen preparation. Figure 1a schematically represents the original polydispersed Ni3Al precipitates in the Ni rich matrix. The three possible type surface profiles of TEM specimens, which result after electrolytic thinning process are illustrated in Figure 1b. c. & d. These various surface profiles could be produced by using different polishing electrolytes and conditions (i.e. temperature and electric current). The matrix-preferential-etching process causes the matrix material to be attacked much more rapidly than the second phase particles. Figure 1b indicated the result. The nonpreferential and precipitate-preferential-etching results are shown in Figures 1c and 1d respectively.

Local bond order parameters for accurate determination of crystal structures in two and three dimensions

2018 ◽  
Vol 20 (42) ◽  
pp. 27059-27068 ◽  
Author(s):  
Hossein Eslami ◽  
Parvin Sedaghat ◽  
Florian Müller-Plathe
Keyword(s):  
Crystal Structures ◽  
Bond Order ◽  
Accurate Determination ◽  
Three Dimensional ◽  
Order Parameters ◽  
Three Dimensions ◽  
Local Order ◽  
Crystalline Structures

Local order parameters for the characterization of liquid and different two- and three-dimensional crystalline structures are presented.

Experimental determination of friction coefficients between thermoplastics and rapid tooled injection mold materials

2005 ◽  
Vol 11 (3) ◽  
pp. 167-173 ◽  
Author(s):  
Mary E. Kinsella ◽  
Blaine Lilly ◽  
Benjamin E. Gardner ◽  
Nick J. Jacobs
Keyword(s):  
Injection Molding ◽  
Accurate Determination ◽  
Rapid Tooling ◽  
Injection Molding Process ◽  
Process Conditions ◽  
Molding Process ◽  
Friction Coefficients ◽  
Content Type ◽  
Temperature Conditions

PurposeTo determine static friction coefficients between rapid tooled materials and thermoplastic materials to better understand ejection force requirements for the injection molding process using rapid‐tooled mold inserts.Design/methodology/approachStatic coefficients of friction were determined for semi‐crystalline high‐density polyethylene (HDPE) and amorphous high‐impact polystyrene (HIPS) against two rapid tooling materials, sintered steel with bronze (LaserForm ST‐100) and stereolithography resin (SL5170), and against P‐20 mold steel. Friction tests, using the ASTM D 1894 standard, were run for all material pairs at room temperature, at typical part ejection temperatures, and at ejection temperatures preceded by processing temperatures. The tests at high temperature were designed to simulate injection molding process conditions.FindingsThe friction coefficients for HDPE were similar on P‐20 Steel, LaserForm ST‐100, and SL5170 Resin at all temperature conditions. The HIPS coefficients, however, varied significantly among tooling materials in heated tests. Both polymers showed highest coefficients on SL5170 Resin at all temperature conditions. Friction coefficients were especially high for HIPS on the SL5170 Resin tooling material.Research limitations/implicationsApplications of these findings must consider that elevated temperature tests more closely simulated the injection‐molding environment, but did not exactly duplicate it.Practical implicationsThe data obtained from these tests allow for more accurate determination of friction conditions and ejection forces, which can improve future design of injection molds using rapid tooling technologies.Originality/valueThis work provides previously unavailable friction data for two common thermoplastics against two rapid tooling materials and one steel tooling material, and under conditions that more closely simulate the injection‐molding environment.

Preparation of millimeter scale second phase particles in aluminum alloys and determination of their mechanical properties

2019 ◽  
Vol 784 ◽  
pp. 68-75 ◽  
Author(s):  
Xinyue Lan ◽  
Kai Li ◽  
Fuxin Wang ◽  
Yanqing Su ◽  
Mingjun Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloys ◽  
Second Phase ◽  
Second Phase Particles

Crystal orientation effects in the x-ray microanalysis of spinels

1992 ◽  
Vol 50 (2) ◽  
pp. 1240-1241
Author(s):  
Ian M. Anderson
Keyword(s):  
Crystal Orientation ◽  
Spinel Phase ◽  
Accurate Determination ◽  
Test Case ◽  
Second Phase ◽  
X Ray ◽  
Impurity Atoms ◽  
Electron Intensity ◽  
The Subject

Compounds with the crystal structure of the mineral spinel (MgAl2O4) provide an interesting test case for the quantitative x-ray microanalysis of crystals. The cations occupy more than one crystallographic site, two thirds occupying the octahedral 16d interstices and one third occupying the tetrahedral 8a interstices of the oxygen anion sublattice (Fd3m). Under dynamical electron diffraction conditions in the AEM, the standing-wave electron intensity on the two sublattices may differ considerably, in turn yielding proportionally different x-ray count rates from the cations on these sublattices. This effect has been exploited to determine the sites of impurity atoms in spinels using the ALCHEMI technique. The strong crystal orientation effect obstructs the accurate determination of the composition of spinels using x-ray microanalysis, however. In the system NiO-TiO2, which is the subject of ongoing investigation, a second phase is always found finely dispersed within the metastable spinel phase. The AEM is the only instrument which provides the high spatial resolution necessary to probe the composition.

The Determination of Spatial Homogeneity in Multiphase Mixtures

1990 ◽  
Vol 48 (1) ◽  
pp. 424-425
Author(s):  
Zülal Misirli ◽  
Burhanettin S. Altan ◽  
Hüseyin Yörücü
Keyword(s):  
Standard Deviation ◽  
Finite Size ◽  
Second Phase ◽  
Spatial Homogeneity ◽  
Ratio Size ◽  
Second Phase Particles ◽  
Relative Standard ◽  
Image Area ◽  
Automated Technique

The modifications of the properties of composite materials by controlling the ratio, size, shape, orientation and spatial distribution of the second phase particles is a well known phenomena. Although there are technique available for the quantifying of most of these parameters, there is no established technique for the determination of the spatial homogeneity; yet this property is also highly influental on the behavior of the material. The aim of this paper is to introduce a fully automated technique to determine the spatial homogeneity of second phase particles.The technique presented in this paper was based on the technique reported by Eisenkolb and Lange and Hirlinger. In this technique the image area was divided by a grid having equal size squares (Fig.1). In a homogeneous mixture the proportion of the second phase would be the same in each square. However, because of the finite size and the agglomeration of particles, the proportion of the second phase varies. This variation is best represented by Relative Standard Deviation, Srel, which is defined as the standard deviation divided by the average. As finer grid sizes are used Srel would naturally increase. It was assumed that for a random dispersion Srel increases linearly as the size of the grid squares becomes smaller. In this study it was shown mathematically that this increase becomes faster when agglomerations are present.

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