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Co-sputtered copper–indium (Cu–In) alloy layers were investigated as precursors for CuInSe2 (CIS) formation. Results of scanning electron microscopy (SEM). (a) Silicon crystals in eutectic as-cast alloy. Scanning electron micrograph (SEM). (b) Primary silicon crystals in hypereutectic as-cast alloy. SEM. This sample was already etched and left for a few days then taken to SEM, I am curious about the "wrinkle-like" features on the surface. Could this be an oxide.


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Alloy sem Driver

Introduction The microstructural characterization of the precipitation process in alloys is a very important aspect in order to understand the formation mechanism and growth kinetics of precipitated phases during its heating because of either the heat treating process or the operation-in-service conditions. Additionally, the microstructure control is a key point to know the degree of hardening after heat treating of the alloys and to assess their mechanical properties after a prolonged exposure at high temperature during the operation of an industrial component.

There are different characterization techniques for microstructure; however, the use of the scanning electron microscopy, SEM, has been very popular for Alloy sem microstructural observation and it has become a power tool for characterization of the phase transformations. Besides, the application of energy-dispersed-spectra, EDS-SEM system to the microstructural characterization has permitted to know not only the morphology of phases, sizes, distribution and then growth kinetics, but also their chemical composition and thus element distribution of the formed phases.

Alloy sem this chapter shows the application of Alloy sem system to the characterization of microstructural of precipitation process in different alloy systems such as Fe-Ni-Al alloy, austenitic stainless steels and Mg-Zn-Al alloy. Precipitation in alloys Phase separation in alloys usually consists of the formation of a supersaturated solid solution by heating the alloy at temperatures higher than the equilibrium solvus line and subsequently quenched rapidly.

This supersaturated solid solution can usually be separated in two or more phases as a result of the isothermal aging at temperatures lower than that of equilibrium. Alloy sem

Phase separation can mainly take place by two mechanisms, nucleation and growth, and spinodal decomposition Porter, Alloy sem The former mechanism consists of the formation of a stable nucleus with a nucleation barrier to overcome and it is characterized by an incubation period. In contrast, the latter one is initiated by the spontaneous formation and subsequent growth of coherent composition fluctuations. The formation of fine second-phase dispersion in a matrix promotes its hardening, known as precipitation hardening.

If the aging Alloy sem alloys continues, it is expected that larger precipitates will grow at the expense of smaller ones which dissolve again given rise to Alloy sem change in the precipitate size distribution Kostorz, These alloys are used in industrial components which require good mechanical strength and oxidation resistance at high temperatures.

SEM Analysis of Precipitation Process in Alloys

The coarsening resistance of precipitates is a key factor Alloy sem keep the high strength at high temperatures in this type of alloys. An alternative to have a good coarsening resistance, it is to have a low value of lattice misfit which maintains a coherent interface between the precipitate and matrix Kostorz, Experimental details An Alloy sem alloy wt.

Vickers hardness was tested for the aged specimens using a load of g. It can be noticed that Alloy sem experimental data fit to a straight line for each temperature. Thus the growth kinetics of coarsening followed the behavior predicted by the Lifshitz-Slyozov-Wagner LSW theory for coarsening controlled by volume diffusion. This fact shows a good agreement with the modified theory for the diffusion-controlled coarsening in ternary alloys Kostorz, which predicts that growth kinetics is similar to that of LSW Alloy sem.


The size distribution of precipitates is shown in Figs. It can be seen that the size distribution is broader and lower than that predicted by the LSW theory because of the high volume fraction of precipitates, which Alloy sem been reported in the coarsening process of several alloy systems. It has been observed that the growth or shrinkage rate of an individual particle depends not only on its normalized radii but also on its local environment. That is, a particle surrounded by several larger particles will grow slower, or Alloy sem faster, than a particle of the same size whose neighbors are smaller.

Alloy sem

Thus, as the Alloy sem fraction increased, the particle size distribution widened increasing the coarsening rate at the same time. Figure 1.

Figure 2. Plot of r3-ro3 vs. Figure 3. Besides, the hardness is almost the same value for prolonged aging at both temperatures. A prolonged aging caused the formation of rectangular plates also aligned in this direction. The coarsening process followed the growth kinetics predicted by the LSW Alloy sem.

Figure 4. Precipitation in austenitic stainless steels The austenitic stainless steels are construction materials for key corrosion-resistant equipment in most of the major industries, particularly in the chemical, petroleum, and nuclear power industries Marshal, This content of chromium allows the formation of the Alloy sem film, which is self-healing in a wide variety of environments. Nitrogen as an alloying element in iron-based alloys is known since the beginning of the last century having been profoundly studied during the last three Alloy sem Nakajima et al.


Nevertheless, nitrogen steels are now not widely used. The reason for the comparatively narrow industrial application lies in Alloy sem old customer skepticism Alloy sem relation to nitrogen as an element causing brittleness in ferritic steels, some technical problems involved with nitrogen into steel, and the insufficient knowledge of the physical nature of nitrogen in iron and its alloys. In the case of austenitic stainless steels, the main driving force in the development of nitrogen-containing steels is due to the higher yield and tensile strengths achieved, compared with conventionally-processed austenitic stainless steels without sacrificing toughness.

Aluminum-silicon Casting Alloys: An Atlas of Microfractographs - كتب Google

It is also important to notice that, in contrast to carbon, nitrogen-containing austenitic stainless steels retain high Alloy sem toughness at low temperatures. Therefore, the higher mechanical properties of nitrogen-containing austenitic stainless steels have made very attractive its application in the power-generation industry, shipbuilding, railways, cryogenic process, chemical equipment, pressure vessels and nuclear industries Nakajima et al. Alloy sem stainless steels are also susceptible to the precipitation of different phases because of the aging for long exposition Alloy sem high temperatures or during continuous cooling after a welding process.

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