Role of Chromium in High-Dose, High-Rate, Elevated Temperature Nitrogen Implantation of Austenitic Stainless Steels

1991 ◽  
Vol 235 ◽  
Author(s):  
D. L. Williamson ◽  
I. Ivanov ◽  
R. Wei ◽  
P. J. Wilbur
Keyword(s):  
Solid Solution ◽  
Elevated Temperature ◽  
Stainless Steels ◽  
Depth Profiling ◽  
Austenitic Stainless Steels ◽  
High Dose Rate ◽  
High Rate ◽  
High Dose ◽  
X Ray Diffraction

ABSTRACTIn order to help establish the role of Cr in high-dose, high-dose-rate, elevated temperature N implantation of austenitic (fcc) stainless steels, similar implantations into fee Ni80Fe20 and Ni80Cr20 alloys have been made and characterized by Auger depth profiling and X-ray diffraction. For the Ni-Fe alloy a shallow layer fcc(∼ 0.2 μm) containing an ordered fee γ'-(Ni0.8Fe0.4)4N phase is induced. In contrast, for the Ni-Cr alloy a much thicker N-containing layer (∼ 0.2 μm) is produced consisting primarily of a high-N solid solution fee phase. The fractions of the implanted N retained in Ni-Fe and Ni-Cr were approximately 10 and 100%, respectively. The mechanisms by which Cr is promoting the deep migration and high retention of N in solid solution are proposed.

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.

The role of needle trauma to the neurovascular bundle region (NVB) and its impact on potency following high-dose-rate (HDR) brachytherapy

Brachytherapy ◽  
2007 ◽  
Vol 6 (2) ◽  
pp. 86
Author(s):  
Michel I. Ghilezan ◽  
J. Vito Antonucci ◽  
Gary S. Gustafson ◽  
Peter Chen ◽  
Michelle Wallace ◽  
...  
Keyword(s):  
Dose Rate ◽  
High Dose Rate ◽  
Neurovascular Bundle ◽  
High Dose ◽  
Hdr Brachytherapy

Formation of Solid Solution and Metallic Nickel Phases During Suspension Plasma Spraying of Co Oxide and Ni Oxide

2021 ◽  
Author(s):  
Vahid Jalilvand ◽  
Ali Dolatabadi ◽  
Christian Moreau ◽  
Saeed Mohammadkhani ◽  
Lionel Roué ◽  
...  
Keyword(s):  
Solid Solution ◽  
Inert Anode ◽  
Metallic Nickel ◽  
Aluminum Production ◽  
X Ray Diffraction ◽  
Oxide Coatings ◽  
Cobalt Nickel ◽  
Sprayed Coatings ◽  
Insight Into

Abstract The focus of this study is the formation of a solid solution and metallic nickel in the cobalt-nickel mixed oxide coatings during suspension plasma spray (SPS) deposition. The (Co,Ni)O solid solution is a potential material for inert anode applications in aluminum production. SPS coatings and in-flight collected particles are studied to gain further insight into the melting and mixing phenomena of the NiO and CoO powders as well as phase formation in the deposited coatings. Moreover, the role of suspension feedstock particle sizes on the microstructure of coatings is discussed. SEM, EDS and X-ray diffraction studies helped better understanding the formation of different crystalline phases within the as-sprayed coatings. It was found that the formation of metallic nickel is possible in the coatings. The results support the importance of substrate temperature on the formation of metallic Ni, so that keeping the substrate at low temperature results in an increase of the Ni content in the coatings. In this study, possible causes for the formation of metallic Ni during spraying are discussed.

scholarly journals Rectal and Bladder Dose Measurements in the Intracavitary Applications of Cervical Cancer Treatment with HDR Afterloading System: Comparison of TPS Data with MOSFET Detector

2019 ◽  
Author(s):  
N Singh ◽  
Sh Ahamed ◽  
A Sinha ◽  
Sh Srivastava ◽  
N K Painuly ◽  
...  
Keyword(s):  
High Dose Rate ◽  
In Vivo Dosimetry ◽  
Intracavitary Brachytherapy ◽  
High Dose ◽  
Gradient Fields ◽  
Calculated Dose ◽  
Mosfet Detector ◽  
Dose Measurements

Background: Intracavitary brachytherapy plays a major role in management of cervical carcinoma. Assessment of dose received by OAR’s therefore becomes crucial for the estimation of radiation toxicities in high dose rate brachytherapy.Objective: The purpose of this study is to evaluate the role of in vivo dosimetry in HDR brachytherapy and to compare the actual doses delivered to OAR’s with those calculated during treatment planning.Materials and Methods: A total of 50 patients were treated with Microselectron HDR. Out of 50 patients, 26 were treated with a dose of 7 Gy and 24 with a dose of 9 Gy, prescribed to point A. Brachytherapy planning and evaluation of dose to the bladder and rectum was done on TPS & in vivo dosimetry was performed using portable MOSFET.Results: The calibration factors calculated for both the dosimeters are almost equal and are 0.984 cGy/mV and 1.0895 cGy/mV. For bladder, dose deviation was found to be within +/- 5% in 28 patients, +/- 5-10% in 14 patients, +/- 10-15% in 4 patients. The deviation between the TPS-calculated dose and the dose measured by MOSFET for rectum was within +/- 5% in 31 patients, +/- 5–10% in 8 patients, and +/- 10–15% in 7 patients.Conclusion: TPS calculated doses were slightly higher than that measured by MOSFET. The use of a small size of MOSFET dosimeter is an efficient method for accurately measuring doses in high-dose gradient fields typically seen in brachytherapy. Therefore, to reduce risk of large errors in the dose delivery, in vivo dosimetry can be done in addition to TPS computations.

Role of Alloying Elements on the Cytotoxic Behavior and Corrosion of Austenitic Stainless Steels

2005 ◽  
pp. 2295-2298
Author(s):  
Y.S. Kim ◽  
Y.R. Yoo ◽  
C.G. Sohn ◽  
Keun Taek Oh ◽  
Kyoung Nam Kim ◽  
...  
Keyword(s):  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Alloying Elements

Zinc diffusion induced precipitation of σ-phase in austenitic stainless steel

2019 ◽  
Vol 116 (6) ◽  
pp. 618
Author(s):  
Nega Setargew ◽  
Daniel J. Parker
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Intermetallic Phase ◽  
Austenitic Stainless Steels ◽  
Austenite Matrix ◽  
Σ Phase ◽  
Intermediate Phases ◽  
Zinc Diffusion

Zinc diffusion-induced degradation of AISI 316LN austenitic stainless steel pot equipment used in 55%Al-Zn and Zn-Al-Mg coating metal baths is described. SEM/EDS analyses results showed that the diffused zinc reacts with nickel from the austenite matrix and results in the formation of Ni-Zn intermetallic compounds. The Ni-Zn intermetallic phase and the nickel depleted zones form a periodic and alternating layered structure and a mechanism for its formation is proposed. The role of cavities and interconnected porosity in zinc vapour diffusion-induced degradation and formation of Ni-Zn intermediate phases is also discussed. The formation of Ni-Zn intermediate phases and the depletion of nickel in the austenite matrix results in the precipitation of σ-phase and α-ferrite in the nickel depleted regions of the matrix. This reaction will lead to increased susceptibility to intergranular cracking and accelerated corrosion of immersed pot equipment in the coating bath. Zinc diffusion induced precipitation of σ-phase in austenitic stainless steels that we are reporting in this work is a new insight with important implications for the performance of austenitic stainless steels in zinc containing metal coating baths and other process industries. This new insight will further lead to improved understanding of the role of substitutional diffusion and the redistribution of alloying elements in the precipitation of σ-phase in austenitic stainless steels.

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