scholarly journals Irradiation Hardening and Microstructure Characterization of Zr -1% Nb During Low Dose Neutron Irradiation

2021 ◽  
Vol 10 (2) ◽  
pp. 63-72
Author(s):  
Carolina Vazquez ◽  
Eugenia Zelaya ◽  
Ana Maria Fortis ◽  
Patricia B. Bozzano
Keyword(s):  
Neutron Irradiation ◽  
Low Dose ◽  
Zirconium Alloys ◽  
Life Time ◽  
Tensile Tests ◽  
Crystal Defects ◽  
Second Phase ◽  
Hydrogen Damage ◽  
Transmission Electron

Due to low neutron absorption cross section, high mechanical strength, high thermal conductivity and good corrosion resistance in water and steam, Zirconium alloys are widely used as fuel cladding material in nuclear reactors. During life-time of a reactor the microstructure of this alloy is affected due to, among other factors, radiation damage and hydrogen damage. In this work mechanical properties changes on neutron irradiated Zr-1wt.% Nb at low temperatures (< 100 °C) and low dose (3.5 ´ 1023 n m-2 (E > 1 MeV)) were correlated with hydrides and crystal defects evolution during irradiation. To achieve this propose, tensile tests of: 1) Non-hydrided and non-irradiated material, 2) Hydrided and non-irradiated material and 3) Hydrided and irradiated material were performed at 25 ºC and 300 ºC. Different phases, hydrides and second phase precipitates were characterized by transmission electron microscopy (TEM) techniques. For the hydrided and irradiated material, the ductility decreased sharply with respect to the hydrided and non-irradiated material, among other factors, due to the change in the microstructure produced mainly by neutron irradiation. Even if the presence of the hydride ζ (zeta) was observed, both in the irradiated and non-irradiated material, tensile tests showed that ζ-hydrides did not affect ductility, since hydrided samples are more ductile than non-hydrided samples.

scholarly journals Characterization of Nanobainitic Structure Obtained in 100Crmnsi6-4 Steel after Industrial Heat Treatment/ Charakteryzacja Struktury Nanobainitycznej Wytworzonej W Handlowej Stali Łożyskowej – 100Crmnsi6-4 W Przemysłowej Obróbce Cieplnej

2014 ◽  
Vol 59 (4) ◽  
pp. 1637-1640 ◽  
Author(s):  
J. Dworecka ◽  
E. Jezierska ◽  
K. Rozniatowski ◽  
W. Swiatnicki
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Treatment Process ◽  
Tensile Tests ◽  
Bearing Steel ◽  
Transformation Kinetics ◽  
Transmission Electron ◽  
Microstructure Parameters ◽  
Static Tensile

Abstract The aim of the work was to produce a nanobainitic structure in the commercial bearing steel - 100CrMnSi6-4 and to characterize its structure and mechanical properties. In order to produce this structure the austempering heat treatment was performed, with parameters that have been selected on the basis of dilatometric measurements of phase transformation kinetics in steel. The heat treatment process was performed in laboratory as well as in industrial furnaces. The obtained structure was characterized using transmission electron microscopy. In order to investigate the effect of the microstructure parameters on the material’s mechanical properties, the hardness, impact strength and static tensile tests have been conducted.

Effect of Second Phase Particles on the Tensile Instability of a Nanostructured Al-1%Si Alloy

2014 ◽  
Vol 783-786 ◽  
pp. 2629-2634 ◽  
Author(s):  
Tian Lin Huang ◽  
Gui Lin Wu ◽  
Qing Liu ◽  
Xiao Xu Huang
Keyword(s):  
Tensile Tests ◽  
Structural Features ◽  
Second Phase ◽  
Commercial Purity ◽  
Localized Deformation ◽  
Dispersed Particles ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
Tensile Instability ◽  
Recovery Annealing

A nanostructured Al-1%Si alloy containing dispersed Si particles was produced by heavily cold-rolling to study the effect of second phase particles on the tensile instability of nanostructured metals. Tensile tests were conducted on the as-deformed sample and the samples after recovery annealing treatments. The structural features of deformed and annealed samples were characterized by transmission electron microscopy. By comparing with the behavior of nanostructured commercial purity Al without dispersed particles, a remarked improvement in the tensile stability was found. This is related to a prevention of localized deformation by the presence of finely dispersed Si particles in the nanoscale matrix structure.

Characterization of neutron irradiation damage in zirconium alloys—an international “round-robin” experiment

1978 ◽  
Vol 36 (1) ◽  
pp. 366-367
Author(s):  
D.O. Northwood ◽  
R.W. Gilbert ◽  
P.M. Kelly ◽  
P.K. Madden ◽  
D. Faulkner ◽  
...  
Keyword(s):  
Zirconium Alloys ◽  
Round Robin ◽  
Irradiation Damage ◽  
Exact Nature ◽  
Dislocation Loops ◽  
The Past ◽  
Irradiation Growth ◽  
Transmission Electron ◽  
International Round

Over the past few years there has been disagreement between laboratories on the exact nature of the damage in irradiated zirconium alloys. The main disagreement has centred on whether or not dislocation loops with c-component Burgers' vectors are formed during the irradiation. Since the presence of c-component loops was required in one of the current theories of irradiation growth and is considered in many other models, it was desirable to clear up this point and others relating to the nature of the damage such as loop size, loop concentration and the nature of the loop population, i.e. vacancy or interstitial. To this end a ‘round-robin’ series of transmission electron microscopy (TEM) examinations of neutron irradiated zirconium alloys was organized and the results are reported herein.The participants in the ‘round-robin’ included laboratories who had previously claimed to have seen evidence for c-component damage. The materials examined included zirconium and Zircaloy-2 irradiated at temperatures from 250-400°C, Table 1, the materials irradiated at 400°C providing samples with dislocation loops large enough to determine the interstitial/vacancy nature by inside/outside contrast techniques.

Microstructural Characterization of Dual and Multiphase Steels Applied to Automotive Industry

2014 ◽  
Vol 775-776 ◽  
pp. 146-150 ◽  
Author(s):  
Cristina Sayuri Fukugauchi ◽  
Antonio dos Reis Faria Neto ◽  
Rosinei Batista Ribeiro ◽  
Marcelo dos Santos Pereira
Keyword(s):  
Mechanical Properties ◽  
Microstructural Characterization ◽  
Tensile Tests ◽  
Ferrite Matrix ◽  
Microstructure Characterization ◽  
Second Phase ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Trip Steels

TRIP (Transformation Induced Plasticity) and DP (Dual-Phase) steels are written in a new series of steels which present excellent mechanical properties. As for microstructure aspect, TRIP steels consist on a ferrite matrix with a second phase dispersion of other constituents, such as bainite, martensite and retained austenite, while dual-phase steels consist on martensite dispersion in a ferrite matrix. In order to identify the different microconstituents present in these materials, microstructure characterization techniques by optical microscopy (using different etchants: LePera, Heat-Tinting and Nital) and scanning electron microscopy were carried out. This being so, microstructures were correlated with mechanical properties of materials, determined by means of tensile tests. It is concluded that steels assisted by TRIP effect have a strength and elongation relation higher than the dual-phase one. With microstructure characterization, it was observed phases present in these materials microstructure.

Surface and Interface Damage Characterization of Reactive Ion Etched MBE Regrown GaAs

1989 ◽  
Vol 163 ◽  
Author(s):  
M.W. Cole ◽  
M. Dutta ◽  
J. Rossabi ◽  
D.D. Smith ◽  
J.L. Lehman
Keyword(s):  
Raman Spectroscopy ◽  
Structural Damage ◽  
Crystal Defects ◽  
Interface Roughness ◽  
Surface And Interface ◽  
Transmission Electron ◽  
Microstructural Evaluation ◽  
Wet Chemical ◽  
Power Densities

AbstractDamage resulting from reactive ion etching (RIE) and wet etching of MBE grown GaAs and the defects generated in subsequent GaAs regrowth was evaluated by Transmission Electron Microscopy (TEM), photoluminescence (PL) , and Raman spectroscopy. The samples were reactively etched with HCl and Cl2 at two power densities; 0.3 W/cm2 and 0.6 W/cm2. A wet chemical (H2O:H3PO4:H2O2) etched sample was used for comparison. The LO phonon intensities measured by room temperature Raman spectroscopy showed a strong correlation to the relative PL intensities, where the HCl sample was found to be inferior to the others. TEM microstructural evaluation showed both HCl RIE samples to have significant interface roughness, with the sample etched at 0.6 W/cm2 showing the most structural damage in the regrowth region. Defect densities for the Cl2. and wet etched samples were two orders of magnitude lower than that of the HCl etched samples. The extent of disorder in the regrowth region was largest for the HCl sample with respect to the Cl2 and wet etched samples. These microstructural and optical results suggest that the H+ ion plays an important role in the generation of crystal defects during the RIE process.

scholarly journals Interface Characterization of Ni/Al Bimetallic Explosively Welded Plate Manufactured with Application of Exceptionally High Detonation Speed

2020 ◽  
Vol 29 (10) ◽  
pp. 6286-6294
Author(s):  
I. Kwiecien ◽  
P. Bobrowski ◽  
M. Janusz-Skuza ◽  
A. Wierzbicka-Miernik ◽  
A. Tarasek ◽  
...  
Keyword(s):  
Second Phase ◽  
Microstructural Characteristics ◽  
Alloy Plate ◽  
Transmission Electron ◽  
Detonation Speed ◽  
In Situ Heating ◽  
The Waves ◽  
Very High

AbstractThe investigation is dedicated to the detailed microstructure characterization of explosively welded clads, in which, exceptionally and for cognitive purposes, a very high detonation speed of about 2800 m/s was used to manufacture bimetallic aluminum-nickel plates. The study involves detailed microstructural characteristics of the bonded zone at micro and nano level, especially focused on the expanded melted regions consisted mostly of Al3Ni, Al3Ni2 and AlNi phases. In situ heating experiment in transmission electron microscope allowed observing microstructure transformation revealing that additionally present metastable Al9Ni2 phase was transformed to Al3Ni and Al3Ni2. Microhardness measurements across the welded zone showed the increase of the microhardness of nickel alloy plate from 153 up to 170 HV when approaching to the Ni201/A1050 interface, while the value for aluminum plate was of 45 HV. Within the melted zones the microhardness was found to be 135 HV and it enormously increased to 850 HV after annealing of the sample at 500 °C. This change was due to the transformation of the interface region from the waves with the melted zones into the continuous layers of two intermetallic phases: Al3Ni and Al3Ni2. The second phase grew at the expense of the Al3Ni.

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