Fatigue and Cyclic Behavior of 304L Stainless Steel in the Presence of Boriding Surface Treatment

2016 ◽  
Vol 703 ◽  
pp. 106-111
Author(s):  
Omar Allaoui ◽  
Lakhdar Taleb
Keyword(s):  
Thermochemical Treatment ◽  
Fatigue Tests ◽  
Cyclic Behavior ◽  
304L Stainless Steel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Life Analysis ◽  
Fatigue Life Analysis ◽  
Boride Phases ◽  
304L Steel

In this work, we will study the cyclic behavior (tension-compression under strain control) and the fatigue of 304L austenitic SS after application of a boriding thermochemical treatment. 304L specimens was borided in a solid medium at 900 °C for 4 hours. The phase analysis of boride layers formed at the surface was performed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The obtained results show that the layers formed on 304L steel contained the following boride phases FeB, Fe2B, CrB, Cr2B, NiB and Ni2B. The fatigue tests show that the boriding treatment improves the life a factor which may be greater than four. The borided specimens show a negative average stress during cycling which may explain the increase of fatigue life. Analysis of the fracture surface by SEM show that crack initiation takes place in the substrate rather than in the boron-treated area.

scholarly journals Preparation and Properties of Nanocellulose from Miscanthus x giganteus

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Valerii A. Barbash ◽  
Olha V. Yashchenko ◽  
Olesia A. Vasylieva
Keyword(s):  
Structural Changes ◽  
Thermochemical Treatment ◽  
Crystallinity Index ◽  
Alkaline Treatment ◽  
X Ray Diffraction ◽  
Miscanthus X Giganteus ◽  
X Ray ◽  
Second Stage ◽  
20 Nm ◽  
Hydrolysis Of

Miscanthus x giganteus stalks were used to make organosolvent pulp and nanocellulose. The organosolvent miscanthus pulp (OMP) was obtained through thermal treatment in the mixture of glacial acetic acid and hydrogen peroxide at the first stage and the alkaline treatment at the second stage. Hydrolysis of the never-dried OМP was carried out by a solution of sulfuric acid with concentrations of 43% and 50% and followed by ultrasound treatment. Structural changes and the crystallinity index of OMP and nanocellulose were studied by SEM and FTIR methods. X-ray diffraction analysis confirmed an increase in the crystallinity of OMP and nanocellulose as a result of thermochemical treatment. We show that nanocellulose has a density of up to 1.6 g/cm3, transparency up to 82%, and a crystallinity index of 76.5%. The AFM method showed that the particles of nanocellulose have a diameter in the range from 10 to 20 nm. A thermogravimetric analysis confirmed that nanocellulose films have a denser structure and lower mass loss in the temperature range of 320–440°C compared to OMP. The obtained nanocellulose films have high tensile strength up to 195 MPa. The nanocellulose obtained from OMP exhibits the improved properties for the preparation of new nanocomposite materials.

Growth Kinetics and Mechanical Characterization of a Hard Boron Coating on a Tool Steel

2017 ◽  
Vol 380 ◽  
pp. 29-34 ◽  
Author(s):  
D. Sánchez Huerta ◽  
N. López Perrusquia ◽  
I. Hilerio Cruz ◽  
M.A. Doñu Ruiz ◽  
E.D. García Bustos ◽  
...  
Keyword(s):  
Activation Energy ◽  
Mechanical Characteristics ◽  
Mechanical Characterization ◽  
Chemical Elements ◽  
Thermochemical Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optimal Classification

The mechanical characteristics are determined to a FeB/Fe2B coating applied in AISI L6 steel tool and blades make to cut paper. The thermochemical treatment was applied at temperatures of 1173, 1223 and 1273 K with permanence time of 0.5, 2 and 3 h for each temperature. The diffusion coefficient and activation energy for each phase is obtained for this boron coating on an AISI L6 steel. HRC test were made to establish the type of adherence (qualitative) and comparing with the VDI 3198 standard and the results were obtaining optimal classification of HF1-HF2 in condition for 3h of the three temperatures. The result by nanoidentation show hardness of 1000 - 2000 HV as well as the Young's modulus for each present phase of the coating. Through micrographs (SEM) are showing thicknesses up to 79.52 ± 18.82 μm for FeB and 97.80 ± 20.01μm for Fe2B, a morphology sawn ́s type is evidence. Through EDS and x-ray diffraction are used to show the chemical elements formed.

scholarly journals In situsynchrotron X-ray diffraction study of strain induced crystallisation of natural rubber during fatigue tests

2012 ◽  
Vol 41 (7) ◽  
pp. 290-295 ◽  
Author(s):  
S. Beurrot-Borgarino ◽  
B. Huneau ◽  
E. Verron ◽  
P. Rublon ◽  
D. Thiaudière ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Diffraction Study ◽  
Fatigue Tests ◽  
X Ray Diffraction ◽  
X Ray

Synthesis, Crystal Chemistry and Magnetism of the Metal-rich Borides MxRh7–xB3 (M = Cr, Mn, Ni; x = 0.39–1) with Th7Fe3-type Structure

2011 ◽  
Vol 66 (12) ◽  
pp. 1241-1247
Author(s):  
Patrick R.N. Misse ◽  
Richard Dronskowski ◽  
Boniface P. T. Fokwa
Keyword(s):  
Melting Furnace ◽  
Structure Type ◽  
Argon Atmosphere ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Arc Melting ◽  
Pauli Paramagnetism ◽  
Powder Samples ◽  
Boride Phases

Powder samples and single crystals of the boride phases MxRh7−xB3 (M = Cr,Mn, Ni; x ≤ 1) have been synthesized from the elements using an arc-melting furnace under purified argon atmosphere in a water-cooled copper crucible. The new phases were characterized from single-crystal and powder X-ray diffraction, as well as semi-quantitative EDX measurements. The obtained phases crystallize in the hexagonal Th7Fe3 structure type (space group P63mc, no. 186, Z = 2). In all cases (M = Cr, Mn, Ni), M is found to preferentially mix with rhodium at only one (6c) of the three available rhodium positions. Pauli paramagnetism was observed in CrxRh7−xB3 (x < 1), whereas both Pauli and temperature-dependent paramagnetisms were found in NiRh6B3.

X-Ray Diffraction Study of Microstructural Changes During Fatigue Damage in Steel Pipelines

2012 ◽  
Author(s):  
Bianca Pinheiro ◽  
Jacky Lesage ◽  
Ilson Pasqualino ◽  
Noureddine Benseddiq ◽  
Edoardo Bemporad
Keyword(s):  
Fatigue Damage ◽  
Fatigue Behavior ◽  
Ion Beam ◽  
Fatigue Tests ◽  
X Ray Diffraction ◽  
Microstructural Changes ◽  
X Ray ◽  
Steel Pipes ◽  
Damage Initiation ◽  
Three Stages

Steel pipes used for oil and gas exploitation undergo the action of cyclic loads that can cause their failure by fatigue. A consistent evaluation of the fatigue behavior should take into account the micromechanisms of fatigue damage initiation, which precede macroscopic cracking and macrocrack propagation. In this work, microstructural changes in terms of variations in microdeformations and residual stresses (macrostresses) are evaluated by X-ray diffraction in real time during alternating bending fatigue tests performed on samples taken from an API 5L X60 grade steel pipe. Three stages of microstructural changes are detected. It is found that their amplitudes and durations are proportional to the level of alternating stress applied. Changes in density and distribution of dislocations are observed by transmission electron microscopy combined with the technique of focused ion beam. To understand the role of the initial dislocation structure, fatigue tests on annealed samples are performed under the same test conditions. Again, three stages of changes are observed, but with an increase in microdeformations during the first stage instead of a decrease as found for as-machined samples, suggesting the influence of the initial state of the dislocation network. The results obtained are very encouraging for the consideration of microstructural evolutions in the development of an indicator of fatigue damage initiation in steel pipes.

scholarly journals A new attack upon the problem of fatigue of metals, using X-ray methods of precision

1936 ◽  
Vol 154 (883) ◽  
pp. 510-539 ◽  
Keyword(s):  
Tensile Stress ◽  
Mild Steel ◽  
Yield Point ◽  
Systematic Study ◽  
Fatigue Tests ◽  
X Ray Diffraction ◽  
X Ray ◽  
Static Tensile ◽  
Static Yield ◽  
Ray Methods

The failure of metals by fatigue has been investigated by applying precise methods of X-ray diffraction to a systematic study of the changes produced in the crystalline structure under various conditions of test. The material used for the experiments was a normalized mild steel (0*1% C). The fatigue tests were of three distinct types involving, respectively, ( a ) cycles of reversed torsional stressed, ( b ) cycles of reversed direct stresses, and ( c ) cycles of alternating direct stresses where the superior stress of the cycle was maintained at a constant value of tensile stress exceeding the static yield point of the material. In addition, comparable observations have been made of the changes in structure arising from the application of static tensile and static torsional stresses of various intensities including those causing fracture.

Fatigue of Zirconia - Bioglass Dental Ceramics

2008 ◽  
Vol 591-593 ◽  
pp. 628-633 ◽  
Author(s):  
Luiz A. Bicalho ◽  
R.C. Souza ◽  
Claudinei dos Santos ◽  
M.J.R. Barboza ◽  
Carlos Antonio Reis Pereira Baptista
Keyword(s):  
Fracture Toughness ◽  
Fatigue Life ◽  
Bending Strength ◽  
Cyclic Fatigue ◽  
Fatigue Tests ◽  
Modulus Of Rupture ◽  
Dental Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Four Point Bending

In this work the cyclic fatigue life of 3mol.%Y2O3-stabilized zirconia polycrystalline ceramics, doped with 5%wt 3CaO.P2O5,-SiO2-MgO, has been investigated. Samples with 5 and 10%wt were cold uniaxial pressed (80MPa) and sintered in air at 1200 and 1300oC for 120 minutes. Sintered samples were characterized by X-Ray diffraction and Scanning Electronic Microscopy. Hardness and fracture toughness were determined using Vicker’s indentation method, and Modulus of Rupture was determined by four-point bending testing. Furthermore, the cyclic fatigue tests were also realized by four-point bending tests, under frequency of 25 Hz and stress ratio, R, of 0.1, for the best condition. In this condition, highly dense samples were obtained and presented values of hardness, fracture toughness and bending strength of 11.3 ±0.1GPa, 6.1±0.4MPa.m1/2 and 320±55MPa, respectively. The increasing of stress level leads to decreasing of the number of cycles and the number of run-out specimens. The stress induced tetragonal-monoclinic (t-m)-ZrO2 transformation, observed by X-Ray diffraction, contributes to the increasing of the fatigue life. Samples 3Y-TZP presents clearly a range of loading conditions where cyclic fatigue can be detected.

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