Metallographic analysis

Gross cracks may be visually observable. Nondestructive testing for the presence of cracks includes using dye penetrant, ultrasonics, and radiography. Determination of the cracking mechanism will require metallographic analysis. 

From metallographic analysis of the sample with composition Ce33.3Sb66.fi, Abulkhaev and Abdusalamova (1989) observed, in addition to the expected CeSb2 phase and CeSb, needle shaped single crystals of unknown composition and structure. Authors believe that this phase is a high temperature modification of CeSb2. 

Metallographic analysis allows the determination of the surface reduction along the fracture and defines the fragile or ductile nature of the fracture. By employing a longitudinal section, it was possible to evaluate the magnitude of corrosion close to the surface of the fracture. 

The metallographic analysis of the reactors with the optical microscope shows not worth mentioning trace of corrosion in the high temperature section of the reactor The elemental analysis of the exposed surface revealed a layer reach in Ni and Fe oxides and depleted in Cr and Mo. These changes affect only a thin layer. In account to the long exposure time of more than 1000 h and the high (up to 0.2 mol/kg) HCl concentration, corrosion rates of alloy 625 in high temperature - low-density supercritical water solutions are definitely low. For such HCl and Oj solutions Ni-base alloys, similar to alloy 625, can be used. 

In the experiment with 0.2 mol/kg HCl the liner was stiffly connected with the Ni-base alloy of the reactor. After experiment, the metallographic analysis revealed that the welding connection has leaked... 

The prepared TiCp/2024 FGM was cut apart radically and axially, and made into metallographic samples. The volume fractions of TiCp in various sections were measured by quantitative metallographic analysis method. 

The distribution of impurities between the main phases of the alloys was studied, since it affects the susceptibility of material to hot cracking during welding and the mechanical properties of welded joints. Metallographic analysis and chemical analysis were carried out with the help of JSM-U3 electron microscope, which had an attachment for energy-dispersive x-ray analysis. For this investigation, test samples were taken from the argon arc welds on 5-mm-thick Al-6Cu-Mn plates. The alloys contained various amounts of Si and Fe the concentration differences of... 

Muravyova (1972) reinvestigated tbe phase equilibria for the 0-33 a/o Ce section (see fig. 2b) of the Ce-Al-Si system by means of X-ray powder and metallographic analysis of 65 alloys which were arc-melted and subsequently annealed for 150-750 h at 500 °C in evacuated silica tubes. The starting materials were 99.0% Ce and 99.90% Al, Si. 

The phase equilibria in the ternary system Ce-Gd-Si have been established by Mokra (1979) by means of X-ray and metallographic analysis of 105 alloys prepared by arc melting and subsequent annealing in evacuated silica capsules for 800 h at 600 °C. The samples were finally quenched in water. Starting materials were Ce 99.56%, Gd 99.85% and Si 99.99%. 

Zmii and Gladyshevskij (1974) presented a partial isothermal section of the system Ce-Mg-Si at 400 °C. Phase equilibria as shown in fig. 12 were determined on the basis of X-ray powder and metallographic analysis of 70 alloys, which were prepared by arc melting, followed by a heat treatment in evacuated silica tubes for 100 h at 400°C. Purity of starting materials was as follows Ce 99.99%, Mg 99.97%, Si 99.99%. 

Phase equilibria in the ternary system Ce-Nd-Si have been determined at 600 °C by Mokra et al. (1978) by means of powder X-ray and metallographic analysis. 115... 

Zarechnyuk et al. (1981) investigated the phase equilibria in an partial isothermal section of the system Gd-Al-Si (0-33 a/o Gd, fig. 24) by means of X-ray and metallographic analysis of 80 samples which were arc melted and subsequently heat treated at 500 °C for 700 h in evacuated silica tubes. Starting materials were 99.85% Gd, 99.99% Al und 99.99% Si. Earlier data obtained by Raman and Steinfink (1967) for the section Gd(Al,, jSij )2 were confirmed. 

Bodak et al. (1978) investigated the phase equilibria in the system Gd-Fe-Si at 800 °C by means by X-ray powder and metallographic analysis of 250 alloys which were prepared by arc melting and subsequent annealing in evacuated silica tubes (800 °C, 720 h). 

Bodak and Gladyshevskij (1969) studied the La-poor region of the La-Co-Si system by means of X-ray powder and metallographic analysis of arc-melted alloys, which subsequently were heat-treated at 800 ° C for 100 h in evacuated silica tubes. An extended solid solubility of Si was observed in LaCojj,, Sio, 9 with the NaZnj3-type, a = 11.33-11.29(1). For 30-33 a/o Si a tetragonal NaZn,3 derivative structure [a = 11.06(9), c= 11.53(1)] was first reported by Bodak and Gladyshevskij (1969) in a later study by Bodak (1979) isotypic behavior was claimed with the structure type of CejNij Sij (I4/mcm,, Cq). No further... 

Bodak and Gladyshevskij (1972) investigated the phase equilibria at 600 °C by means of X-ray and metallographic analysis of 120 alloys. Samples were prepared by... 

A partial isothermal section of the Sc-poor region (0-67 a/o Sc) has been investigated by Kotur et al. (1977) by means of X-ray powder and metallographic analysis of arc-melted samples, which were then annealed at 800 °C and some of them at 700 ° C. Starting materials were 99.9% pure. 

Samples were investigated in a cast (arc-melted) as well as in annealed condition, a) 1000°C, 65 h in high vacuum, radiation quenched, b) 500°C, 750 h in evacuated silica tubes. Starting materials were 99.9% pure. Congruent melting behavior was confirmed by metallographic analysis. 

The structure of the sample cross sections was studied by the method of metallographic analysis. It included the investigation of the total structure of the coatings and determining their thickness. 

ASTM A 262) provide relative susceptibility only for austenitic stainless steels. These tests have little usefulness in freshwater environments. A metallographic analysis performed after test samples are exposed provides the most useful information about susceptibility to intergranular corrosion (ASTM E 3 and E 80). 

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