Download File PDF Astm E 13 Standard Test Methods For Determining. Astm E 13 Standard Test . ASTM E EPUB - ASTM E – ASTM E EBOOK DOWNLOAD - Download Citation | On Jan 1,, ASTM and others published ASTM E() ASTM E EPUB DOWNLOAD - Astm e 96 ePub download - Author. Per Ad- merk. Com DIN STEELS FOR. St52 / st 3 / st 3n din structural steel high tensile plate .

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1 These test methods are under the jurisdiction of ASTM Committee E04 on. Metallography Last previous edition approved as E – 96() ´2. DOI. 4 ASTM E 96 PDF - download ASTM E()e2 Standard Test Methods Og. Publication Borrow this book to access EPUB and PDF files. Jeffries' standard procedure according to ASTM E was used to There are two million PDF, ePub and other ebook files that every visitor can read online .

This article has been cited by other articles in PMC. Microwave sintering MS and conventional sintering CS methods were used to fabricate zirconia specimens. The dwelling time was 20 minutes for MS and 20 minutes, 2, 10, and 40 hours for CS. The density and the grain size of the sintered zirconia blocks were measured. Total transmission measurements were taken using a spectrophotometer.

Two-way analysis of variance model was used for the analysis and performed at a type-one error rate of 0. The mean grain size ranged from , nm for Lava and , nm for KaVo. The mean light transmittance values of Lava and KaVo were To obtain more translucent dental zirconia restorations, shorter sintering times should be considered. Fundamentally, translucency is highly dependent on light scattering.

The aim of this study was to investigate the pattern of changes in the density, grain size, and translucency of dental zirconia according to various sintering conditions time and method , as well as the effects of the sintering conditions on the translucency of dental zirconia. Our hypothesis in this study was that a change in the sintering conditions would change the translucency of the zirconia core.

The sintering temperatures for MS and CS were set according to the instructions of the manufacturers. The dwelling time was 20 minutes for MS and 20 min 2, 10, or 40 hr for CS four conditions. The detailed sintering conditions are shown in Table 1. The blocks were cut in a container filled with water using low speed diamond saw. The core was then polished using 1,grit wet sandpaper Buehler Ltd.

Table 1 Open in a separate window The density of the sintered specimens was measured using the Archimedes method in water, following the ISO standard. Measurements were performed at wavelengths ranging from to nm at 10 nm intervals. Measurements were repeated three times per specimen. Afterwards, all specimens were cleaned ultrasonically in acetone for 10 min and then dried for 24 hr.

The recalescence detected and measured during the equiaxed transition was of the order of 3. The interphase velocities varied between 0. Also, the presence of ceramic particles in ZA alloys affected the thermodynamic local conditions and the kinetics of nucleation, producing a finer microstructure.

Introduction A metal-matrix composite MMC is composite material with at least two constituent parts, with one being a metal. The other material may be a different metal or another material, such as a ceramic or organic compound. The matrix is the monolithic material into which the reinforcement is embedded and is completely continuous. The reinforcement does not always serve a purely structural task but is also used to change physical properties such as wear resistance, friction coefficient, or thermal conductivity.

The reinforcement can be either continuous or discontinuous [ 1 ].

Effects of the sintering conditions of dental zirconia ceramics on the grain size and translucency

The aspect ratio of the reinforcement is an important quantity, because the degree of load transfer from the matrix to the reinforcement is directly proportional to the reinforcement aspect ratio. Particle or short fiber reinforced metals have a much lower aspect ratio, so they exhibit lower strengths than their continuous fiber counterparts, although the properties of these composites are much more isotropic [ 1 , 2 ]. Metal-matrix composites can be processed by several techniques.

Some of these important techniques are liquid-state processes casting or liquid infiltration, squeeze casting, or pressure infiltration , solid-state processes diffusion bonding, deformation processing, powder processing, sinter-forging, and deposition techniques , in situ processes, and spray-forming of particulate MMCs [ 2 ].

In general, ceramic reinforcements fibers, whiskers, or particles have a coefficient of thermal expansion lower than that of most metallic matrices. On the other hand, when the composite is subjected to a temperature change, thermal stresses are generated in both components [ 3 ].

The development of composites obtained by solidification of alloys has made remarkable progress and their applications in automotive and aerospace industries have increased in recent decades. Among these applications, the most current one is the zinc and aluminum base. It is important for metallurgical processes to establish relationships between thermal parameters and solidification structures, because the solidification structure encompasses morphological aspects of different types of grains columnar, equiaxed, or columnar-to-equiaxed transition and dendrite structure primary, secondary, or tertiary along the distribution and state of aggregation of the second reinforcing phase.

The interaction between the parameters involved in the columnar-to-equiaxed transition CET phenomenon, which has gained considerable attention over the last decades, allows understanding the structure of ingot castings and optimizing the industrial practice [ 4 — 18 ].

The characteristics of metal-matrix composite materials are determined by their microstructure and internal interfaces, which are affected by their production and thermal mechanical prehistory. The microstructure covers the structure of the matrix and the reinforced phase. The second phase is characterized by its volume percentage, its kind, its size, its distribution, and its orientation.

Local varying internal tension due to the different thermal expansion behavior of the two phases is an additional influencing factor [ 1 , 2 , 19 ].

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From the past research it is known that rules developed for solidification of unreinforced metals cannot be applied directly to metal matrix composites. An important tool in the study of alloy solidification is the Bridgman furnace, which produces well-controlled steady-state directional solidification conditions. Directional solidification can be used to investigate solidification modes, analyzing the thermal parameter thermal gradient and growth velocity variation during the solidification process.

Nevertheless, alloy solidification in engineering castings is generally dendritic and thermal parameters are neither measured nor constant over the course of solidification [ 17 — 21 ]. The present work is focused on the study of the effect of directional heat extraction on the silicon-carbide SiC distribution in an aluminum matrix composite and on the CET position in directionally solidified samples.

To this end, Zn wt. The thermal parameters cooling rates, temperature gradients, and interphase velocities were then measured, and their influence on the solidification microstructure of the MMCs was analyzed.

Their compositions are shown in Table 1. The samples were melted and solidified directionally upwards in an experimental setup see Figure 1 described elsewhere [ 16 , 17 ]. The procedure was as follows: at first, the liquid metal inside the mold in the furnace was allowed to reach the selected temperature.

Once a uniform temperature was reached, less than 1 degree of difference recorded between the five thermocouples located at different positions in the melt, the furnace power was turned off and the melt was allowed to solidify from the bottom. Heat was extracted using a cooling system which consisted of a copper disk attached to a copper coil.

1. Introduction

Figure 1: Details of the vertical experimental device. The thermocouples were previously calibrated using four temperature points: demineralized water at the freezing and boiling points corrected by atmospheric pressure and zinc The samples were melted in ceramic molds i.

The liquidus and solidus temperatures for each alloy were determined using two methods. The DTA measurements were carried out with a charge of mg of premelted samples in alumina crucibles in an Argon atmosphere. The liquidus and solidus temperatures were taken from the heating and cooling curves as usual [ 22 , 23 ]. This criterion was chosen to allow undercooling to occur before solidification and possible recalescence during solidification of equiaxed grains.

The position of the transition was located by visual observation and optical microscopy and the distance from the chill zone of the sample was measured with a ruler.

The number of particles was determined by means of a grid method, dividing one section in 64 squares of 20 20 mm uniformly distributed. The number of repetitions in each case ensured a representative distribution in each sample. The density of average sizes of particles was determined by quantifying the repetitions of size of different particles in the grid.

Astm E112 Grain Size Pdf

An average of the distribution of sizes was obtained. Particle size ranged between 1. The microstructure was analyzed with optical and scanning electron microscopy SEM. The distribution of elements in the microstructure was determined using EDXA. Results and Discussion 3.

Macrostructures and Microstructures Eight experiments were performed with different alloy and composite compositions and cooling rates. As reported elsewhere for other alloys [ 10 , 11 , 16 , 17 ], the transition is not sharp, showing a zone where some equiaxed grains coexist with columnar grains.

Also, no effect of the set of the thermocouples in the transition is observed; that is, the set of the thermocouples in the transition neither acted as nucleating sites nor changed the solidification structure.

The solidification microstructure of Zn wt. The eutectoid is formed during the final stage of solidification, from dendrites and peritectic through a transformation at K, following the Zn-Al phase diagram.

This eutectoid has a typical plate-like form of and sheets and a standard and finer eutectic structure. With the addition of silicon to the alloy, the phases and microstructures were the same as those in ZA27 alloys.

Evaluation (as per ASTM E112 and DIN EN ISO 643) and classification of micrographic images

However, silicon in the microstructure appears in two forms: in solution and as a precipitate [ 16 ]. As an example, in Figures 4 a , 4 b , and 4 c the distributions of Si, Al and Zn in the matrix of Figure 4 c are shown. Figure 3: Microstructure of a Zn wt.

Figure 4 c shows the matrix with silicon precipitates and with SiC particles, respectively. The precipitates appear mostly in the dendritic cores, which indicates that the precipitates form in the melt and the grains possibly nucleate on them. Moreover, the particles appear mostly in the interdendritic regions as opposed to the silicon precipitates, as shown in Figure 4 d.

The SiC particles are clearly distinguished from the silicon precipitates because the precipitates have a light gray color, whereas the particles have a dark gray color, and because the precipitates have irregular contours, whereas the particles have sharp corners. The samples present some degree of porosity, which increases from the bottom to the top of the casting, following the increase in the number of SiC particles Figure 4 e.This indicates a large effect of particle addition in the resulting microstructure.

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This test method covers the procedure for assessing the adhesion of coating films to substrate by using a knife. The core was then polished using 1,grit wet sandpaper Buehler Ltd. Further, ASTM test method D includes several annexes, each describing the use of a different testing device that can produce different adhesion values on the same coating , and the ASTM D inter-laboratory study for coatings on concrete includes the use of seven different test devices, all of which operate a little differently.

These kinds of techniques depended on the Cu-Al-Ni alloy powder, which was prepared by either an inert gas atomization process or mechanical alloying of elemental powders in a high-energy ball mill under inert gas atmosphere [ 15 ].

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