Nanostructure Formation in Austenitic Stainless Steel

2008 ◽  
Vol 140 ◽  
pp. 173-178 ◽  
Author(s):  
Agnieszka T. Krawczynska ◽  
Małgorzata Lewandowska ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Stainless Steels ◽  
Structural Changes ◽  
Annealing Temperature ◽  
True Strain ◽  
Nano Structure ◽  
Uniform Microstructure ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Different Temperatures ◽  
Nano Grains

Samples of 316LVM stainless steels were hydrostatically extruded in a multi-step process to a total true strain of 1,84 and subsequently annealed at different temperatures. The structural changes occurring as a result of HE and annealing were observed using a transmission electron microscope. The microhardness of the samples was measured using a load of 200g. The results show that hydrostatic extrusion results in a uniform microstructure characterized by a high density of nano-twins. Subsequent annealing at 600°C produces a partial transformation to a nano structure of average grain size 54 nm. At an annealing temperature of 700°C a fullyrecrystallized uniform microstructure consisting of 68 nm diameter nano-grains was formed. It should be noted that 700°C is much lower than that required to recrystallize a micro-grained alloy of the same composition. The microstructural changes which occurred during annealing have a significant effect on the mechanical properties. The microhardness after HE increased following annealing at 500°C. However, annealing at 800°C resulted in a drop in microhardness, indicating the occurrence of grain growth.

Grain Size Effects on the Oxidation of Fe-33Ni-19Cr Alloy at 700°C

2014 ◽  
Vol 699 ◽  
pp. 151-156
Author(s):  
Noraziana Parimin ◽  
Esah Hamzah ◽  
Astuty Amrin
Keyword(s):  
Grain Size ◽  
Annealing Temperature ◽  
Oxidation Kinetic ◽  
Solution Treatment ◽  
Oxidation Behaviour ◽  
Solution Annealing ◽  
X Ray ◽  
Average Grain Size ◽  
Different Temperatures ◽  
Different Grain Size

The effect of different grain size on the oxidation of Fe-33Ni-19Cr alloy was discussed. The present paper focuses on the oxidation behaviour in dry air at temperature of 700oC with respect to oxidation kinetics. Solution treatment was applied to Fe-33Ni-19Cr alloy by means of different solution annealing temperature to alter the average grain size of the specimens. Solution heat treatments were carried out on Fe-Ni-Cr alloys at three different temperatures, namely, 1000oC, 1100oC and 1200oC. The results showed that the average grain size increased with increase in solution annealing temperature that was significantly affecting the oxidation kinetic of the materials. Optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were employed in this study to analyse the oxidation behaviour of solution-annealed samples. Smaller grain size improves the protective oxidation behaviour by enhancing spallation resistance and reducing oxidation rate. Spallation resistance correlates with a reduction in texture of the oxide layers.

scholarly journals Study of Phase Formation Processes in Li2ZrO3 Ceramics Obtained by Mechanochemical Synthesis

Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 21
Author(s):  
Maxim V. Zdorovets ◽  
Artem L. Kozlovskiy ◽  
Baurzhan Abyshev ◽  
Talgat A. Yensepbayev ◽  
Rizahan U. Uzbekgaliyev ◽  
...  
Keyword(s):  
Phase Formation ◽  
Structural Changes ◽  
Annealing Temperature ◽  
Solid Phase ◽  
Image Data ◽  
Formation Processes ◽  
Ceramic Structure ◽  
Current Voltage ◽  
Average Grain Size ◽  
Temperature Dependences

The article is dedicated to the study of the phase formation processes in Li2ZrO3 ceramics obtained by the method of solid phase synthesis. Interest in these types of ceramics is due to their great potential for use as blanket materials in thermonuclear reactors, as well as being one of the candidates for tritium breeder materials. Analysis of the morphological features of the synthesized ceramics depending on the annealing temperature showed that the average grain size is 90–110 nm; meanwhile the degree of homogeneity is more than 90% according to electronic image data processing results. The temperature dependences of changes in the structural and conducting characteristics, as well as the phase transformation dynamics, have been established. It has been determined that a change in the phase composition by displacing the impurity LiO and ZrO2 phases results in the compaction of ceramics, as well as a decrease in their porosity. These structural changes are due to the displacement of LiO and ZrO2 impurity phases from the ceramic structure and their transformation into the Li2ZrO3 phase. During research, the following phase transformations that directly depend on the annealing temperature were established: LiO/ZrO2/Li2ZrO3 → LiO/Li2ZrO3 → Li2ZrO3. During analysis of the obtained current-voltage characteristics, depending on the annealing temperature, it was discovered that the formation of the Li2ZrO3 ordered phase in the structure results in a rise in resistance by three orders of magnitude, which indicates the dielectric nature of the ceramics.

Recrystallization in Nanostructured Austenitic Stainless Steel

2008 ◽  
Vol 584-586 ◽  
pp. 966-970 ◽  
Author(s):  
Agnieszka T. Krawczynska ◽  
Małgorzata Lewandowska ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Grain Growth ◽  
Structural Changes ◽  
True Strain ◽  
Equivalent Diameter ◽  
Uniform Microstructure ◽  
Lower Annealing Temperature ◽  
Average Size ◽  
Induced Changes

Recrystallization and grain growth were studied in an austenitic stainless steel 316LVM processed by hydrostatic extrusion (HE) to a total true strain of 2. HE processing produces in this material the microstructure which consists of nanoscale twins on average 19 nm in width and 168 nm in length. The samples after HE were annealed at various temperatures for 1 hour. The structural changes were investigated using TEM. The heat induced changes in nanotwinned austenitic steel are significantly different when compared to the ones in a conventionally deformed material. Microstructural changes take place at lower annealing temperature. Annealing at 600°C brings about a partial a nanostructure reorganization into nanograin of average size 54 nm. An uniform microstructure with nanograins of 68 nm in equivalent diameter was obtained after annealing at 700°C whereas conventional 316LVM steel fully recrystallizes after annealing at 900°C for 1h. Annealing at higher temperatures results in grain growth.

scholarly journals Structural Changes in Nickel Silicide Thin Films under the Presence of Al and Ga

2010 ◽  
Vol 638-642 ◽  
pp. 2938-2943 ◽  
Author(s):  
A.V. Mogilatenko ◽  
Frank Allenstein ◽  
M.A. Schubert ◽  
Meiken Falke ◽  
G. Beddies ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Structural Changes ◽  
Annealing Temperature ◽  
Nickel Silicide ◽  
Subsequent Annealing ◽  
Formation Temperature ◽  
Transmission Electron

Thin Ni/Al and Ni/Ga layers of different atomic ratios were codeposited onto Si(001) at room temperature followed by subsequent annealing. Influence of annealing temperature on morphology and composition of ternary disilicide NiSi2-xAlx and NiSi2-xGax layers was investigated by transmission electron microscopy. Addition of Al or Ga leads to a decrease of the disilicide formation temperature from 700°C down to at least 500°C. Depending on the composition closed, uniformly oriented NiSi2-xAlx and NiSi2-xGax layers were observed after annealing at 900°C, whereas reaction of a pure Ni film with Si leads to the island formation with a mixture of A- and B-type orientations.

Research on Hot-Rolling Technics of a Nickel-Based Corrosion Resistant Alloy

2011 ◽  
Vol 199-200 ◽  
pp. 1861-1864
Author(s):  
Yan Fang Li
Keyword(s):  
Mechanical Properties ◽  
Hot Rolling ◽  
Annealing Temperature ◽  
True Strain ◽  
Rolling Temperature ◽  
Different Temperatures ◽  
Temperature Ranges ◽  
Corrosion Resistant Alloy ◽  
Hot Rolling Mill ◽  
Hot Rolled

To improve the hot-rolled processing rate and mechanical properties of Monel alloy plates, its hot-rolling and heat treatment technics were researched, and reasonable hot-rolling temperature and annealing temperature were designed. Through the hot-rolling tests of Monel alloy plates ingots under the condition of different temperatures with a hot-rolling mill, the true stress and true strain curves were measured, the regularity of the flow stress influenced by temperature was investigated, and the hot-rolling temperature was ensured. We also did some study on the effects of annealing temperature on the mechanical properties and metallographs. The results show the reasonable hot-rolling temperature of Monel alloy plates ranges between 1050°C and 1150°C, and its annealing temperature ranges between 650°C and 750°C.

Influence of Deformation Parameters on the Structure in Selected Intermetallic from Al-Fe Diagram

2013 ◽  
Vol 212 ◽  
pp. 63-66 ◽  
Author(s):  
Magdalena Jabłońska ◽  
Dariusz Kuc ◽  
Iwona Bednarczyk
Keyword(s):  
Structural Changes ◽  
Materials Science ◽  
Low Cost ◽  
Intermetallic Phase ◽  
Industrial Applications ◽  
Internal Variables ◽  
Treatment Technology ◽  
University Of Technology ◽  
Transmission Electron ◽  
Different Temperatures

Department of Materials Science at Silesian University of Technology since 10 years conducts researches to learn about the structural phenomena which occur during hot plastic treatment which are aimed at elaboration of a technology of heat and plastic treatment of selected alloys from Al-Fe diagram. The iron aluminides have been among the most widely studied intermetallics because their low cost, low density, good wear oxidation and corrosion resistance, to create wide prospects for their industrial applications, for components of machines working at a high temperature and in corrosive environment. The problem limiting their application is low plasticity and brittle cracking susceptibility. Consequently, the research of intermetallic-phase based alloys focuses on their plasticity. For the development of thermo-plastic treatment technology, it is necessary to determine internal variables describing the structure of an alloys being deformed is the inhomogeneity, grain size, as well as the grains misorientation angles and texture. The paper presents the course of structural changes of Fe-38Al with Zr, B Mo and C additions under the influence of hot plastic deformation with application of a few different temperatures of the process with given speed of deformation. For the structure and substructure investigations were used a light microscopy and transmission electron microscopy.

In Situ Tem Study of Reactions in Iron/amorphous Carbon Layered Thin Films

1995 ◽  
Vol 382 ◽  
Author(s):  
Toshio Itoh ◽  
Robert Sinclair
Keyword(s):  
Grain Size ◽  
Amorphous Carbon ◽  
Layered Structure ◽  
Annealing Temperature ◽  
In Situ Tem ◽  
Dc Sputtering ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Deposited Films

ABSTRACTReactions between Fe and amorphous carbon (a-C) below 600ºC have been investigated. In situ annealing in a transmission electron microscopy (TEM) was performed on a-C/Fe/a-C trilayer films deposited by DC sputtering. As-deposited films showed a well defined tri-layered structure and an average Fe grain size of about 50Å. Cementite (Fe3C) grains appeared in the Fe layer by annealing around 300ºC. As the annealing temperature was raised, the number and size of the cementite grains increased. When the annealing temperature reached 500ºC, the Fe layer completely turned into cementite with an average grain size of 1000Å. At this point the film still kept a well defined tri-layered structure even though some parts of the cementitelayer agglomerated. Above 500ºC, the cementite layer started to “move” into the a-C leaving graphite behind. Graphite formed in this process is strongly textured with the (0002) graphite basal planes parallel to the surface of the moving cementite. This process is concluded to be carbide mediated crystallization of a-C, similar to silicide mediated crystallization of silicon in Ni-Si and Pd-Si systems.

Comparing the Role of Dislocations during Plastic Deformation of Nanocrystalline Nickel and Coarse-Grained Nickel during Cold Rolling

2008 ◽  
Vol 1090 ◽  
Author(s):  
Andreas Kulovits ◽  
Scott M Mao ◽  
Jorg M Wiezorek
Keyword(s):  
Plastic Deformation ◽  
Cold Rolling ◽  
True Strain ◽  
Grain Morphology ◽  
Coarse Grained ◽  
X Ray Diffraction ◽  
Grain Boundary Character ◽  
Transmission Electron ◽  
Average Grain Size

AbstractWe investigated plastic deformation of fully dense electrodeposited nanocrystalline (NC) Ni with an average grain size of 30-40nm. We studied the microstructural evolution during cold rolling of NC Ni to a reduction in thickness up to 76% (true strain equivalent ∼1.42). We determined changes in texture, grain morphology, grain boundary character and grain sizes as a function of cold rolling strain, using X-ray diffraction and transmission electron microscopy TEM. We compared our results of the NC Ni with our own results for cold rolled coarse grained (CG) Ni. Differences and similarities in deformation behavior are discussed with respect to well documented findings in the literature.

A STUDY ON THE PRECIPITATION OF Ge-RICH NANOPARTICLES IN A LUMINESCENT (Er, Ge) CO-DOPED SiO2 FILM SPUTTERED WITH Ar + O2 PLASMA

2006 ◽  
Vol 05 (04n05) ◽  
pp. 493-498
Author(s):  
C. L. HENG ◽  
Y. J. LI ◽  
J. MAYANDI ◽  
T. G. FINSTAD ◽  
S. JØRGENSEN ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Rf Magnetron Sputtering ◽  
Sio2 Film ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Diffraction Patterns ◽  
Amorphous States ◽  
Co Doped

We report the photoluminescence (PL) from an ( Er , Ge ) co-doped SiO 2 film deposited by rf-magnetron sputtering in an Ar + O 2 ambience. The sample film was annealed in N 2 for 30 min at different temperatures. The PL intensity increases as the annealing temperature increases from 700 to 1000°C, and drops to very weak after 1100°C annealing. High-resolution transmission electron microscopy (TEM) observation shows that there are some Ge -rich nanoparticles precipitated after 700°C annealing, and more clusters precipitated after 1000°C annealing. However, no Ge nanocrystals were found in these films, the diffraction patterns are always halo which indicates that the precipitated clusters are in amorphous states. X-ray photoelectron spectroscopy (XPS) analysis indicates the Ge in the nanoclusters is mostly in an oxidized state and the oxidation state of Er increases with increasing annealing temperature.

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