Effects of Carbide Precipitate Formation on the Change in Ultrasonic Velocity in Austenitic Stainless Steels

2014 ◽  
Author(s):  
Taira Okita ◽  
Junji Etoh ◽  
Mitsuyuki Sagisaka ◽  
Takashi Matsunaga ◽  
Yoshihiro Isobe
Keyword(s):  
Stainless Steels ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Austenitic Stainless Steels ◽  
Velocity Change ◽  
Precipitate Formation ◽  
Annealing Conditions ◽  
The Matrix ◽  
Velocity Changes ◽  
Carbide Precipitate

Ultrasonic tests were conducted for 304 type austenitic stainless steels with different annealing conditions and effects of carbide precipitate formation on the velocity changes were evaluated. The velocity increased with higher annealing temperature and/or longer annealing time. SEM observations indicated that carbide precipitates were formed mainly on grain boundaries. Results show that it is not the precipitation itself but the removal of carbon from the matrix that determines the velocity change.

Decarburization of 0.21C-1.3Mn-0.2Si Steel for Hot Stamping at Various Heating Temperatures

2011 ◽  
Vol 172-174 ◽  
pp. 887-892 ◽  
Author(s):  
Koutarou Hayashi ◽  
Toshinobu Nishibata ◽  
Nobusato Kojima ◽  
Masanori Kajihara
Keyword(s):  
Annealing Time ◽  
Single Phase ◽  
Annealing Temperature ◽  
Volume Diffusion ◽  
Hot Stamping ◽  
Ambient Atmosphere ◽  
Uniform Thickness ◽  
Two Phase ◽  
Annealing Conditions ◽  
Parabolic Relationship

In order to examine the decarburization behavior in the hot stamping (HS) method, the dependence of the microstructure evolution on the annealing temperature was experimentally studied using a Fe-0.21 mass% C-1.3 mass% Mn-0.2 mass% Si steel. The steel was isothermally annealed in the temperature range ofT= 773-1173 K for various times oft= 100-12800 s in an ambient atmosphere. Here, the steel possesses the ferrite (α) + cementite (θ) two-phase microstructure atT= 773-923 K, the α + austenite (γ) two-phase microstructure atT= 1013-1073 K, and the γ single-phase microstructure atT= 1093-1173 K. During annealing atT= 1013-1073 K fort= 1600 s, however, the α layer with a uniform thickness is formed at the surface of the steel due to decarburization and gradually grows into the inside. Such formation of the a layer was not clearly observed atT973 K and T1093 K. Thus, the formation of the α layer hardly occurs under the HS annealing conditions. AtT= 1033 K, the thickness of the α layer is mostly proportional to the square root of the annealing time. Such a relationship is called the parabolic relationship. Furthermore, the grain size of the α layer monotonically increases with increasing annealing time. Hence, the parabolic relationship guarantees that the growth of the α layer is controlled by volume diffusion.

Formation of AlN in the N Added 18Cr Ferritic Stainless Steels

2005 ◽  
Vol 486-487 ◽  
pp. 428-431 ◽  
Author(s):  
H.C. Kim ◽  
Je Hyun Lee ◽  
Y.G. Heon ◽  
Chang Yong Jo ◽  
Jae Won Kim ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Ferritic Stainless Steels ◽  
The Matrix ◽  
Formation Behavior ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Phase Characterization

Al addition is known to enhance corrosion resistance and high temperature properties in ferritic and austenitic stainless steels. Due to the addition of Al, formation and characteristic of nitride were studied in Al added 18Cr stainless steels. The phase diagram and segregation were estimated with addition of Al in 18Cr stainless steels by the Thermo-calc program. Formation behavior of the AlN phase was studied by observing the solid/liquid interface through directional solidification and the phase characterization was performed by XRD in the extracted precipitates from the matrix. It was confirmed that the AlN phase formed at the cell boundary from the liquid in 3 and 5 wt.% Al added 18Cr stainless steels.

Effects of long-period superstructures on plastic properties in Al-rich TiAl single crystals

2004 ◽  
Vol 842 ◽  
Author(s):  
Takayoshi Nakano ◽  
Koutaro Hayashi ◽  
Yukichi Umakoshi ◽  
Yu-Lung Chiu ◽  
Patrick Veyssière
Keyword(s):  
Single Crystals ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Microscopic Level ◽  
Vector Group ◽  
Two Phase ◽  
Plastic Properties ◽  
Long Period ◽  
The Matrix ◽  
Ti Particles

ABSTRACTIn Al-rich TiAl crystals, several long-period superstructures may appear depending on Al composition, annealing temperature and annealing time. Amongst these, Al5Ti3 and h-Al2Ti contain pure Al (002) layers, as in the L10 structure of the matrix, alternating with Ti (002) layers that exhibit an ordered arrangement of the Al atoms in excess. In single crystals with compositions ranging from Ti-54.7at.%Al to Ti-62.5at.%Al annealed at 1200°C, the Al5Ti3 long-period superstructure embedded in the L10 matrix develops with increasing Al concentration to finally transform fully into h-Al2Ti for Ti-62.5at.%Al. On the other hand, Al5Ti3 precipitates grow with annealing time at 500°C in Ti-58.0at.%Al.The effects of the Al5Ti3 and h-Al2Ti superstructures on slip properties of 1/2<110] ordinary dislocations are examined both at a macroscopic and a microscopic level. The CRSS for 1/2<110] ordinary slip increases with Al5Ti3 ordering depending on Al composition, or of annealing time in the case of Ti-58.0at.%Al. Dislocations with 1/2<110] Burgers vector group into fourfold configurations to avoid the trailing of extended APBs in Al5Ti3. The CRSS for slip in the <110] direction further increases with the formation of h-Al2Ti particles within the L10 matrix in Ti-62.5at.%Al. By contrast, Ti-62.5at.%Al fully transformed into Al5Ti3 exhibits a CRSS significantly lower than that of the two-phase alloy.

scholarly journals Влияние термического отжига на свойства многослойных зеркал Mo/Be

2019 ◽  
Vol 89 (11) ◽  
pp. 1783
Author(s):  
Р.М. Смертин ◽  
С.А. Гарахин ◽  
C.Ю. Зуев ◽  
А.Н. Нечай ◽  
Н.В. Полковников ◽  
...  
Keyword(s):  
Reflection Coefficient ◽  
Thermal Annealing ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Thermal Action ◽  
Normal Incidence ◽  
Multilayer Mirrors ◽  
X Ray ◽  
Annealing Conditions ◽  
Reflection Maximum

AbstractThe influence of thermal action on X-ray optics performance and structure of films and transition regions in multilayer Mo/Be mirrors optimized for a reflection maximum in the interval 11.2–11.4 nm at normal incidence has been considered. The annealing temperature reached 300°C and the annealing time was 1 and 4 h. It has been shown that after thermal annealing in vacuum for 1 h at 300°C, the reflection coefficient rises; however, when the annealing time grows to 4 h, it drops. Grains in molybdenum films become finer, and the profiles of transition regions change from exponential to linear. The period of multilayer mirrors has remained the same under all annealing conditions.

Comparison Of Thermally- And Irradiation-Induced Grain Boundary Segregation In Austenitic Stainless Steels

1991 ◽  
Vol 238 ◽  
Author(s):  
Edward A. Kenik
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Stainless Steels ◽  
Analytical Electron Microscopy ◽  
Boundary Segregation ◽  
Austenitic Stainless Steels ◽  
Chromium Depletion ◽  
Thermal Sensitization ◽  
The Matrix ◽  
Radiation Induced

ABSTRACTSegregation at grain boundaries in austenitic stainless steels sensitized by either thermal annealing or irradiation was studied by analytical electron microscopy. Characterization of grain boundary compositions in both types of materials was performed by high spatial resolution (≥2 nm) X-ray microanalysis. Whereas similar chromium depletion is observed in both processes, there are differences in the behavior of the other alloying elements and in the mechanisms responsible for the segregation. In thermal sensitization, the nickel/iron ratio and the silicon level observed at grain boundaries are similar to those for the matrix. In cases where little or no precipitation occurs, co-segregation of phosphorus, chromium, and molybdenum occurs at boundaries and interfaces. For radiation sensitization, radiation-induced segregation (RIS) results in enrichment of nickel, silicon, and, in certain cases, phosphorus and in depletion of iron at grain boundaries. There appears to be some synergism between segregation of nickel and silicon, which increases the magnitude of RIS effects. Grain boundary precipitation is often observed in both thermally- and irradiation-sensitized materials. However, the nature and origins of the two types of precipitation are different. The formation of chromium-enriched grain boundary carbides is the cause of the chromium depletion in thermal sensitization. In contrast, the precipitates produced by irradiation are enriched in nickel and silicon and depleted in chromium relative to the matrix and therefore are the result of RIS. Results for thermal- and radiation-induced segregation in manganese-stabilized austenites are compared to that for nickel-stabilized austenites.

Study on Antibacterial Properties of SUSXM7 Cu- Bearing Austenitic Stainless Steel

2013 ◽  
Vol 652-654 ◽  
pp. 997-1001
Author(s):  
Yan Mei Zhang ◽  
Kang Qin ◽  
Qing Ping Du ◽  
Jia Qiang Huang ◽  
Ge Guo Shuai ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Heat Treatment ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Antibacterial Properties ◽  
Austenitic Stainless Steels ◽  
Solution Treated ◽  
The Matrix ◽  
Suitable Amount ◽  
And Staphylococcus Aureus

SUSXM7 Cu-bearing austenitic stainless stee1 was conducted with special antibacterial heat treatment and antibacterial properties of the steel were studied. The experimental results show that a suitable amount of ε-Cu phases can precipitate from the matrix of SUSXM7 steel after solution treated at 1100 °C and aging treated at 650 - 850 °C. ε-Cu phases are granular with diameter of 100 - 200 nm. SUSXM7 Cu-bearing austenitic stainless steels possess excellent antibacterial properties. Antibacterial rates against two typical bacteria of Escherichia coli and Staphylococcus aureus surpass 99.0％ and are basically equal to that of Cu-bearing austenitic antibacterial stainless steel researched widely now.

Radiation Damage Studies with the HVEM

1972 ◽  
Vol 30 ◽  
pp. 680-681
Author(s):  
J. J. Laidler ◽  
B. Mastel
Keyword(s):  
Radiation Damage ◽  
Stainless Steels ◽  
Volume Expansion ◽  
Austenitic Stainless Steels ◽  
Test Facility ◽  
Fast Breeder Reactors ◽  
Breeder Reactors ◽  
Under Construction ◽  
Development Laboratory ◽  
Insight Into

One of the major materials problems encountered in the development of fast breeder reactors for commercial power generation is the phenomenon of swelling in core structural components and fuel cladding. This volume expansion, which is due to the retention of lattice vacancies by agglomeration into large polyhedral clusters (voids), may amount to ten percent or greater at goal fluences in some austenitic stainless steels. From a design standpoint, this is an undesirable situation, and it is necessary to obtain experimental confirmation that such excessive volume expansion will not occur in materials selected for core applications in the Fast Flux Test Facility, the prototypic LMFBR now under construction at the Hanford Engineering Development Laboratory (HEDL). The HEDL JEM-1000 1 MeV electron microscope is being used to provide an insight into trends of radiation damage accumulation in stainless steels, since it is possible to produce atom displacements at an accelerated rate with 1 MeV electrons, while the specimen is under continuous observation.

Strain-induced martensite effects on transgranular carbide precipitation in type 304 stainless steels

1991 ◽  
Vol 49 ◽  
pp. 604-605
Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D. Matlock
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Stress Corrosion Cracking ◽  
Stainless Steels ◽  
Deformation Twin ◽  
Austenitic Stainless Steels ◽  
Carbide Precipitation ◽  
Strain Induced Martensite ◽  
Type 304

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.

Oxidation behavior of 26Cr-16Ni and AISI 309 austenitic stainless steels in air flow at 1,173 K

2015 ◽  
Vol 57 (7-8) ◽  
pp. 597-601 ◽  
Author(s):  
Peeraya Pipatnukun ◽  
Panyawat Wangyao ◽  
Gobboon Lothongkum
Keyword(s):  
Stainless Steels ◽  
Oxidation Behavior ◽  
Air Flow ◽  
Austenitic Stainless Steels
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