Internal Friction Influenced by Hydrogen in Super Duplex Stainless Steels

2005 ◽  
Vol 502 ◽  
pp. 345-350
Author(s):  
Toshio Kuroda ◽  
Katsuyuki Nakade ◽  
Kenji Ikeuchi
Keyword(s):  
Internal Friction ◽  
Stainless Steels ◽  
Sigma Phase ◽  
Peak Height ◽  
Phase Precipitation ◽  
Internal Friction Peak ◽  
Hydrogen Charging ◽  
Super Duplex Stainless Steels ◽  
Two Peaks ◽  
Friction Analysis

The influence of microstructure concerning sigma phase on hydrogen behavior was investigated by means of internal friction analysis. After hydrogen charging, a sharp significant internal friction peak by hydrogen in austenite of as-received specimen was observed at 245K for a frequency of 1.5Hz. However, the peak height in the specimen precipitated significant sigma phase was substantially lower than in as-received specimen since hydrogen in austenite have a concentration lower by sigma phase precipitation. In addition, the broadening and scattering of the internal friction peak was clearly identified by interaction between hydrogen and sigma phase. It means that the two peaks associated with hydrogen in the both sigma phase and austenite were considered to be overlapped. Consequently, it was clearly confirmed that hydrogen entered in the sigma phase lattice and hydrogen was also trapped at sigma/austenite interfaces.

Development of the Snoek Anelastic Relaxation Correlated with Oxygen in β-Ti Alloys

2019 ◽  
Vol 298 ◽  
pp. 59-63 ◽  
Author(s):  
Zheng Cun Zhou ◽  
J. Du ◽  
S.Y. Gu ◽  
Y.J. Yan
Keyword(s):  
Internal Friction ◽  
Physical And Mechanical Properties ◽  
Peak Height ◽  
Relaxation Peak ◽  
Interstitial Oxygen ◽  
Internal Friction Peak ◽  
Β Phase ◽  
Ti Alloys ◽  
Interstitial Atoms ◽  
The Stability

The β-Ti alloys exhibit excellent shape memory effect and superelastic properties. The interstitial atoms in the alloys have important effect on their physical and mechanical properties. For the interstitial atoms, the internal friction technique can be used to detect their distributions and status in the alloys. The anelastic relaxation in β-Ti alloys is discussed in this paper. β-Ti alloys possesses bcc (body center body) structure. The oxygen (O) atoms in in the alloys is difficult to be removed. The O atoms located at the octahedral sites in the alloys will produce relaxation under cycle stress. In addition, the interaction between the interstitial atoms and substitute atoms, e.g., Nb-O,Ti-O can also produce relaxation. Therefore, the observed relaxational internal friction peak during the measuring of internal friction is widened. The widened multiple relaxation peak can be revolved into Debye,s elemental peaks in Ti-based alloys. The relaxation peak is associated with oxygen movements in lattices under the application of cycle stress and the interactions of oxygen-substitute atoms in metastable β phase (βM) phase for the water-cooled specimens and in the stable β (βS) phase for the as-sintered specimens. The damping peak height is not only associated with the interstitial oxygen, but also the stability and number of βM in the alloys.

Secondary Phases Precipitation in the 2510 Duplex Stainless Steel

2009 ◽  
Vol 1242 ◽  
Author(s):  
Arturo Reyes ◽  
Irene Calliari ◽  
Emilio Ramous ◽  
Michela Zanellato ◽  
Mattia Merlin
Keyword(s):  
Stainless Steel ◽  
Stainless Steels ◽  
Sigma Phase ◽  
Secondary Phases ◽  
Heat Treated ◽  
Duplex Steel ◽  
Super Duplex Stainless Steels ◽  
History Of ◽  
Short Times ◽  
Steel Heat

ABSTRACTA lot of duplex and super duplex stainless steels are prone to secondary phases but with different sequence and kinetic which depend on the chemical composition and thermo-mechanical history of the steel. In this paper the results of secondary phase's determination in a welding grade 2510 duplex steel, heat treated at 850–1050°C for 3–30 min are presented. The precipitation stars at grain boundaries with a consistent ferrite transformation for short times. The noses of the TTP curves are at 1000°C (sigma phase) and at 900°C (chi phase) with a partial transformation of chi to sigma, as evidenced in 2205 and 2507 grades.

scholarly journals Internal Friction of Li7La3Zr2O12 Based Lithium Ionic Conductors

2016 ◽  
Vol 61 (1) ◽  
pp. 21-24
Author(s):  
X.P. Wang ◽  
L. Song ◽  
J. Hu ◽  
Y.P. Xia ◽  
Y. Xia ◽  
...  
Keyword(s):  
Internal Friction ◽  
Tetragonal Phase ◽  
Diffusion Processes ◽  
Low Frequency ◽  
Peak Height ◽  
Cubic Phase ◽  
Ionic Conductors ◽  
Internal Friction Peak ◽  
Lithium Ions ◽  
Diffusion Mechanisms

The diffusion mechanisms of lithium ions in tetragonal phase as well as in Al and Nb stabilized cubic Li7La3Zr2O12 compounds were investigated by low-frequency internal friction technique. In the cubic Li7La3Zr2O12 phase, a remarkable relaxation-type internal friction peak PC with a peak height up to 0.12 was observed in the temperature range from 15°C to 60°C. In the tetragonal phase however, the height of the PT peak dropped to 0.01. The obvious difference of the relaxation strength between the cubic and tetragonal phases is due to the different distribution of lithium ions in lattice, ordered in the tetragonal phase and disordered in the cubic phase. Based on the crystalline structure of the cubic garnet-type Li7La3Zr2O12 compound, it is suggested that the high internal friction peak in the cubic phase may be attributed to two diffusion processes of lithium ions: 96h↔96h and 96h↔24d.

Snoek Relaxation in bcc Metals and High Damping β-Ti Alloys

2009 ◽  
Vol 614 ◽  
pp. 175-180 ◽  
Author(s):  
Fu Xing Yin ◽  
Li Ming Yu ◽  
De Hai Ping ◽  
Satoshi Iwasaki
Keyword(s):  
Internal Friction ◽  
Temperature Stability ◽  
Relaxation Mechanism ◽  
Peak Height ◽  
Damping Capacity ◽  
Internal Friction Peak ◽  
Friction Mechanism ◽  
Bcc Metals ◽  
Temperature Position ◽  
Snoek Relaxation

The Snoek relaxation, a specific point-defect induced anelastic relaxation phenomenon, is characteristic of an internal friction peak in bcc metals with interstitial solutes. Such internal friction mechanism has not been applied in the development of high damping alloy while grain boundary and twin boundary featured anelastic relaxations are applied in some high damping alloys. In this paper, the fundamental principles and experimental results concerning the Snoek relaxation are reviewed, and the feasibility to apply the Snoek relaxation mechanism into high damping alloys is discussed. Due to the peak-shape behavior in the Snoek relaxation type damping, composition design of a high damping alloys should takes temperature position, broadness and also peak height into account. Ti-Nb-O and Ti-V-Cr-O alloys are designed and fabricated by CCLM casting in our laboratory. It is conformed that the damping behaviors of the alloys are of Snoek relaxation type showing obvious frequency and temperature dependence. While the broadened damping peak caused by the substitutional solutes is advantage to improve the temperature stability of damping capacity, a large concentration of interstitial solute and texture control are required to improve the reduced damping capacity.

Hydrogen-Induced Mechanical Losses in Oxygen-Free Copper

2012 ◽  
Vol 184 ◽  
pp. 122-127 ◽  
Author(s):  
Mykola Ivanchenko ◽  
Yuriy Yagodzinskyy ◽  
H. Hänninen
Keyword(s):  
High Temperature ◽  
Internal Friction ◽  
Oxygen Content ◽  
Hydrogen Atoms ◽  
Internal Friction Peak ◽  
Exponential Factor ◽  
Hydrogen Charging ◽  
High Temperature Component ◽  
Temperature Component ◽  
High Temperature Components

Two oxygen-free copper grades with purity of 99.99 % were studied by means of free decay inverted torsion pendulum at the temperature range of 90 – 300 K and frequencies of 0.5 – 2 Hz. One copper grade was oxygen free electrolytically refined copper with oxygen content of 1.2 wt. ppm. The other one was oxygen-free phosphorous-alloyed grade with oxygen content less than 5 wt. ppm and phosphorous content of 30 – 70 wt. ppm. Electrochemical hydrogen charging induces a complex internal friction peak in the studied copper grades. The observed internal friction peak has a relaxation origin with apparent activation enthalpy and pre-exponential factor for the oxygen-free grade of 0.276 ± 0.002 eV and 10-11.59 ± 0.08 s, respectively. The internal friction peak can be fitted by three broadened Debye peaks (P1, P2 and P3) with activation enthalpies and pre-exponential factors of 0.248 ± 0.003 eV and 10-11.4 ± 0.4 s; 0.297 ± 0.004 eV and 10-11.8 ± 0.2 s; 0.36 ± 0.04 eV and 10-12.7 ± 1.4 s, respectively. Phosphorous doping markedly reduces the height of the observed peak. It was also shown that prior deformation by tension suppresses high-temperature components of the complex internal friction peak. Mechanism of relaxation is presumably caused by interaction of H – H pairs (low-temperature component, peak P1), interaction of hydrogen atoms with dislocations (P2) and interaction of hydrogen with impurities (high-temperature component, peak P3). Absorption of hydrogen in the studied copper grades during electrochemical hydrogen charging was confirmed by the thermal desorption method.

Internal Friction Study of Vacancy Hardening in B2 Fe Al Alloys

2012 ◽  
Vol 184 ◽  
pp. 81-86 ◽  
Author(s):  
Yoichi Nishino ◽  
Kazuya Ogawa ◽  
H. Tanaka
Keyword(s):  
Plastic Strain ◽  
Internal Friction ◽  
Strain Amplitude ◽  
Peak Height ◽  
Dislocation Motion ◽  
Al Alloys ◽  
Anomalous Increase ◽  
Internal Friction Peak ◽  
Quenching Temperature ◽  
Friction Study

nternal friction behaviour of B2 FeAl alloys has been examined to reveal the correlation of the microplasticity and thermal vacancies. The internal friction peak for Fe60Al40 appears at around 550 K, and the peak height increases with increasing quenching temperature. The curves of internal friction against the strain amplitude shift to larger strain amplitude as the quenching temperature increases. Analysis of the amplitude-dependent internal friction provides the plastic strain of the order of 10-9 as a function of effective stress on dislocation motion. It is found that the microflow stress at the plastic strain of 1×10-9 increases linearly with the square root of the net peak height. Remarkably, the microflow stress decreases with rising temperature but turns to increase above 500 K when measured after holding for 1 h at test temperatures. The anomalous increase in the microflow stress is caused by the creation of thermal vacancies at intermediate temperatures.

scholarly journals Internal Friction on AISI 304 Stainless Steels with Low Tensile Deformations at Temperatures between−50 and 20C

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
T. F. A. Santos ◽  
M. S. Andrade
Keyword(s):  
Internal Friction ◽  
Stainless Steels ◽  
True Strain ◽  
Austenitic Stainless Steels ◽  
Torsion Pendulum ◽  
Internal Friction Peak ◽  
Aisi 304 ◽  
Degree Of Deformation ◽  
Hexagonal Close Packed ◽  
Damping Behavior

Austenitic stainless steels specimens were deformed by tension in temperatures in the range of−50Cto 20Cand 0.03 to 0.12 true strain, in order to obtain different volumetric fractions ofε(hexagonal close packed) andα′(body centered cubic) strain induced martensites. The morphology, distribution and volumetric fractions of the martensites were characterized by metallography and dilatometry analysis and quantified by ferrite detector measurements. The damping behavior of specimens with different volumetric fractions of martensites was studied in an inverted torsion pendulum in the 40Cto 400Crange. Theε- andα′-martensites reversion was observed in the temperature range of 50C–200Cand 500C–800C, respectively, by dilatometry. Internal friction curves in function of temperature of the deformed samples presented internal friction peaks. The first internal friction peak is related to sum of the amount ofε- andα′-martensites. For low deformations it aligns around 130Cand it is related only to theε→γreverse transformation. The peak situated around 350Cincreases with the specimen degree of deformation and is, probably, related to the presence ofα′/γinterfaces, and deformed austenite.

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