Stimulation of plasma-spark sintering of mixtures of oxide-non-oxide components by adding a solid solution TaB2‒NbC and through a nickel melt in mixtures of metal powders

2021 ◽  
Vol 1 (2) ◽  
pp. 14-29
Author(s):  
A. V. Hmelov

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2008 ◽  
Vol 569 ◽  
pp. 93-96 ◽  
Author(s):  
Yong Hwan Kim ◽  
S.I. Kwun

The phases formed in the wide-gap region brazed with Ni-14Cr-10Co-3.5Al-2.5Ta-2.8B filler metal powder in IN738 superalloy were investigated by electron backscatter diffraction (EBSD). The wide-gap brazing process was carried out in a vacuum of 2×10-5 torr at 1503 K. The region brazed with filler metal powders had a microstructure consisting of two kinds of eutectic colonies, one is Ni solid solution-CrB eutectic and the other is Ni solid solution-Ni3B eutectic. EBSD pattern analysis revealed that the CrB phase had orthorhombic structure with lattice parameters of a=0.297, b=0.786 and c=0.293 nm, and the Ni3B phase had orthorhombic structure with lattice parameters of a=0.439, b=0.522 and c=0.662 nm. The cuboidal-shaped phase precipitated in the Ni solid solution was found to be the γ' (Ni3Al) phase, which had cubic structure with lattice parameter of a=0.357 nm.


2015 ◽  
Vol 245 ◽  
pp. 230-237 ◽  
Author(s):  
Yuriy Nikolaevich Kulchin ◽  
Nikolay Gennadievich Galkin ◽  
Evgenii P. Subbotin ◽  
Vasiliy M. Dolgorook ◽  
Dmitrii S. Yatsko

The article discusses the formation of coatings with magnetic properties on non-magnetic substrates by the method of additive technology of metal powders using high power pulsed laser radiation. An instrumental base for the development of methods for creating local magnetic zones of a given configuration has been described. Approaches to create methods of additive welding of solid solution magnetic zones on the basis of micro-powders of metal alloys have been developed. The coatings with soft magnetic properties on the basis of powders of bronze and iron-containing "Inconel" alloy on non-magnetic substrates were obtained by laser welding. The structural inhomogeneity at the interface of the substrate and the solid solution were studied. Data on hardness and magnetic properties were obtained for formed magnetically soft materials.


Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.


Author(s):  
E. A. Elfont ◽  
R. B. Tobin ◽  
D. G. Colton ◽  
M. A. Mehlman

Summary5,-5'-diphenyl-2-thiohydantoin (DPTH) is an effective inhibitor of thyroxine (T4) stimulation of α-glycerophosphate dehydrogenase in rat liver mitochondria. Because this finding indicated a possible tool for future study of the mode of action of thyroxine, the ultrastructural and biochemical effects of DPTH and/or thyroxine on rat liver mere investigated.Rats were fed either standard or DPTH (0.06%) diet for 30 days before T4 (250 ug/kg/day) was injected. Injection of T4 occurred daily for 10 days prior to sacrifice. After removal of the liver and kidneys, part of the tissue was frozen at -50°C for later biocheailcal analyses, while the rest was prefixed in buffered 3.5X glutaraldehyde (390 mOs) and post-fixed in buffered 1Z OsO4 (376 mOs). Tissues were embedded in Araldlte 502 and the sections examined in a Zeiss EM 9S.Hepatocytes from hyperthyroid rats (Fig. 2) demonstrated enlarged and more numerous mitochondria than those of controls (Fig. 1). Glycogen was almost totally absent from the cytoplasm of the T4-treated rats.


Author(s):  
A. Christou ◽  
J. V. Foltz ◽  
N. Brown

In general, all BCC transition metals have been observed to twin under appropriate conditions. At the present time various experimental reports of solid solution effects on BCC metals have been made. Indications are that solid solution effects are important in the formation of twins. The formation of twins in metals and alloys may be explained in terms of dislocation mechanisms. It has been suggested that twins are nucleated by the achievement of local stress-concentration of the order of 15 to 45 times the applied stress. Prietner and Leslie have found that twins in BCC metals are nucleated at intersections of (110) and (112) or (112) and (112) type of planes.In this paper, observations are reported of a transmission microscope study of the iron manganese series under conditions in which twins both were and were not formed. High strain rates produced by shock loading provided the appropriate deformation conditions. The workhardening mechanisms of one alloy (Fe - 7.37 wt% Mn) were studied in detail.


Author(s):  
Jordi Marti ◽  
Timothy E. Howson ◽  
David Kratz ◽  
John K. Tien

The previous paper briefly described the fine microstructure of a mechanically alloyed oxide dispersion strengthened nickel-base solid solution. This note examines the fine microstructure of another mechanically alloyed system. This alloy differs from the one described previously in that it is more generously endowed with coherent precipitate γ forming elements A1 and Ti and it contains a higher volume fraction of the finely dispersed Y2O3 oxide. An interesting question to answer in the comparative study of the creep and stress rupture of these two ODS systems is the role of the precipitate γ' in the mechanisms of creep and stress rupture in alloys already containing oxide dispersoids.The nominal chemical composition of this alloy is Ni - 20%Cr - 2.5%Ti - 1.5% A1 - 1.3%Y203 by weight. The system receives a three stage heat treatment-- the first designed to produce a coarse grain structure similar to the solid solution alloy but with a smaller grain aspect ratio of about ten.


Author(s):  
R. M. Anderson

Aluminum-copper-silicon thin films have been considered as an interconnection metallurgy for integrated circuit applications. Various schemes have been proposed to incorporate small percent-ages of silicon into films that typically contain two to five percent copper. We undertook a study of the total effect of silicon on the aluminum copper film as revealed by transmission electron microscopy, scanning electron microscopy, x-ray diffraction and ion microprobe techniques as a function of the various deposition methods.X-ray investigations noted a change in solid solution concentration as a function of Si content before and after heat-treatment. The amount of solid solution in the Al increased with heat-treatment for films with ≥2% silicon and decreased for films <2% silicon.


Author(s):  
S. Herd ◽  
S. M. Mader

Single crystal films in (001) orientation, about 1500 Å thick, were produced by R-F sputtering of Al + 4 wt % Cu onto cleaved KCl at 150°C substrate temperature. The as-deposited films contained numerous θ-CuAl2 particles (C16 structure) about 0.1μ in size. They were transferred onto Mo screens, solution treated and rapidly cooled (within about ½ min) so as to retain a homogeneous solid solution. Subsequently, the films were aged in vacuum at various temperatures in order to induce precipitation and to compare structures and morphologies of precipitate particles in Al-Cu films with those found in age hardened bulk material.Aging for 3 weeks at 60°C or 48 hrs at 100°C did not produce any detectable change in high resolution micrographs or diffraction patterns. In this range Guinier-Preston zones (GP) form in quenched bulk material. The absence of GP in the present experiments in this aging range is perhaps due to the cooling rate employed, which might be more equivalent to an aged and reverted bulk material than to a quenched one.


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