Controlling diffusion in Ni/Al reactive multilayers by Nb-alloying

2017 ◽  
Vol 111 (17) ◽  
pp. 173902 ◽  
Author(s):  
Volker Schnabel ◽  
Alla S. Sologubenko ◽  
Stefano Danzi ◽  
Güven Kurtuldu ◽  
Ralph Spolenak
Keyword(s):  
Nb Alloying

The Origin of Corrosion Resistance Change Induced by Sn and Nb Alloying in Zr Alloys

2020 ◽  
Author(s):  
Rong Yuan ◽  
Xie Yao-Ping ◽  
Tong Li ◽  
Chen-Hao Xu ◽  
Mei-Yi Yao ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Resistance Change ◽  
Nb Alloying ◽  
Zr Alloys

Microstructure, nano-mechanical characterization, and fretting wear behavior of plasma surface Cr-Nb alloying on γ-TiAl

2020 ◽  
pp. 135065012093983
Author(s):  
Dongbo Wei ◽  
Fengkun Li ◽  
Xiangfei Wei ◽  
Tomasz Liskiewicz ◽  
Krzysztof J Kubiak ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Wear Resistance ◽  
Friction Coefficient ◽  
Wear Behavior ◽  
Wear Test ◽  
Wear Scar ◽  
Fretting Wear ◽  
Friction Behavior ◽  
Plasma Surface ◽  
Nb Alloying

In this study, surface Cr-Nb alloying was realized on γ-TiAl using double glow plasma hollow cathode discharge technique. An inter-diffusion layer was generated under the surface, composed of Cr2Nb intermetallic compounds. After Cr-Nb alloying, the surface nanohardness of γ-TiAl increased from 5.65 to 11.61 GPa. The surface H/E and H3/E2 increased from 3.37 to 5.98 and from 0.64 to 4.15, respectively. Cr-Nb alloying and its effect on fretting wear were investigated. The surface treatment resulted in improved plastic deformation and fretting wear resistance of γ-TiAl. The fretting wear test showed that an average friction coefficient of γ-TiAl against Si3N4 ball was significantly decreased after Cr-Nb alloying. The fluctuation of friction coefficient during running-in stage was significantly improved. The friction behavior of both γ-TiAl before and after Cr-Nb alloying could be divided into distinctive stages including formation of debris, flaking, formation of crack, and delamination. It was observed that the high hardness, resistance to plastic deformation, and fatigue resistance of γ-TiAl after Cr-Nb alloying could inhibit the formation of debris and delamination during friction test. The fretting wear scar area and the maximum wear scar depth were decreased, indicating that the wear resistance of γ-TiAl has been greatly improved after Cr-Nb alloying. The results indicated that plasma surface Cr-Nb alloying is an effective way for improving the fretting wear resistance of γ-TiAl in aviation area.

SURFACE Nb-ALLOYING ON 0.4C–13Cr STAINLESS STEEL: MICROSTRUCTURE AND TRIBOLOGICAL BEHAVIOR

2016 ◽  
Vol 23 (04) ◽  
pp. 1650017 ◽  
Author(s):  
SHENGWANG YU ◽  
KAI YOU ◽  
XIAOZHEN LIU ◽  
YIHUI ZHANG ◽  
ZHENXIA WANG ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Friction And Wear ◽  
Tribological Behavior ◽  
Alloyed Steel ◽  
Formation Mechanisms ◽  
Surface Alloying ◽  
Steel Microstructure ◽  
Glow Plasma ◽  
Nb Alloying ◽  
Plasma Surface Alloying

0.4C–13Cr stainless steel was alloyed with niobium using double glow plasma surface alloying and tribological properties of Nb-alloyed steel such as hardness, friction and wear were measured. Effects of the alloying temperature on microstructure and the tribological behavior of the alloyed steel were investigated compared with untreated steel. Formation mechanisms of Nb-alloyed layers and increased wear resistance were also studied. The result shows that after surface Nb-alloying treatment, the 0.4C–13Cr steel exhibits a diffusion adhesion at the alloyed layer/substrate interface and improved tribological property. The friction coefficient of Nb-alloyed steel is decreased by about 0.3–0.45 and the wear rate after Nb-alloying is only 2–5% of untreated steel.

Effect of Nb alloying additions on the characteristics of anodic oxide films on zirconium and their stability in NaOH solution

2009 ◽  
Vol 14 (8) ◽  
pp. 1451-1455 ◽  
Author(s):  
Francesco Rosalbino ◽  
Daniele Macciò ◽  
Adriana Saccone ◽  
Emma Angelini ◽  
Stefano Delfino
Keyword(s):  
Oxide Films ◽  
Anodic Oxide ◽  
Alloying Additions ◽  
Anodic Oxide Films ◽  
Naoh Solution ◽  
Nb Alloying

Investigation of CGHAZ Simulations of Low-Carbon Bainitic Steels

2021 ◽  
Vol 1016 ◽  
pp. 1869-1874
Author(s):  
Tun Tun Nyo ◽  
Antti Kaijalainen ◽  
Jaakko Hannula ◽  
Jukka I. Kömi
Keyword(s):  
Impact Toughness ◽  
Heat Affected Zone ◽  
Base Material ◽  
Strength Properties ◽  
Coarse Grained ◽  
Low Carbon ◽  
Bainitic Steels ◽  
Produce Steel ◽  
Welding Procedure ◽  
Nb Alloying

The effect of ten different combinations with various amounts of niobium (0-0.6 wt.%) and chromium (1-4 wt.%) on weldability and mechanical properties of thermomechanically rolled and direct-quenched low-carbon (0.035 wt.%) microalloyed bainitic steel were investigated. Two compositions were alloyed with boron to increase the hardenability, and two with titanium to improve the toughness properties in heat affected zone. The target of the study was to produce steel with 700 MPa yield strength combined with good impact toughness. Coarse grained heat affected zone (CGHAZ) simulations were performed using the Gleeble 3800 thermomechanical simulator to evaluate the weldability of the investigated steels using cooling time from 800 °C to 500 °C (t8/5) of 5 s and 15 s to simulate different heat inputs in actual welding procedure. Microstructures were characterized using light optical microscopy, and hardness profiles of simulated heat affected zones were determined as well as Charpy-V impact toughness at-40 °C and-60 °C. Shorter t8/5 time (5 s) produced generally better impact toughness properties compared to longer t8/5 -time (15 s). Steels with 4 % Cr had the highest impact energies. Generally, more softening occurred with longer t8/5-time (15 s). However, Cr and Nb alloying decreased the amount of softening in the CGHAZ region, especially with longer t8/5 -time. These results indicate that even with higher t8/5 -time, it is possible to achieve strength properties equivalent to the base material in the CGHAZ region by Cr and Nb alloying.

Structural Refinement of 15%Cr-2%Mo White Irons

2010 ◽  
Vol 457 ◽  
pp. 231-236 ◽  
Author(s):  
Adel Nofal ◽  
Reham Reda ◽  
Khaled M. Ibrahim ◽  
Abdel-Hamid Hussein
Keyword(s):  
Growth Process ◽  
Xrd Analysis ◽  
Optical Image ◽  
Image Analyzer ◽  
Formation Temperature ◽  
Solidification Behavior ◽  
Structural Refinement ◽  
Fine Carbide ◽  
Available Carbon ◽  
Nb Alloying

This research aims at studying the structural refinement of 15%Cr-2%Mo hypo- and hypereutectic white irons through dynamic solidification and Nb-alloying (1-2%Nb). Solidification behavior was studied using DSC. Microstructure investigation and analysis were performed using optical, image analyzer as well as SEM, EDX and XRD analysis. Refinement mechanisms proposed involved both enhancing nucleation and altering the growth process of the primary and eutectic phases either by fragmentation of the primary growing phase in the case of dynamic solidification or by consuming the available carbon from the liquid and hence the amount and size of M7C3 will decrease in the case of addition of Nb-alloying. Nb has higher affinity to carbon during solidification, higher formation temperature than the main microstructure constituents and forms fine carbide so Nb achieves refinement of the microstructure.

Nb-C Alloyed Layer Prepared on TiAl Alloys by Plasma Treatments and its First-Principles Investigation

2011 ◽  
Vol 399-401 ◽  
pp. 1903-1908
Author(s):  
Xiao Ping Liu ◽  
Pei Lin Ce ◽  
Zhen Xia Wang ◽  
Zhi Yong He
Keyword(s):  
First Principles ◽  
First Principle ◽  
Alloyed Layer ◽  
Tial Alloys ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Forming Mechanism ◽  
Plasma Treatments ◽  
Depth Increase ◽  
Nb Alloying

A Nb-C alloyed layer formed on TiAl by plasma Nb alloying followed by carburization was investigated. The alloyed layer was characterized using SEM, TEM, XRD and GDS. Effects of Nb alloying and the carburizing atmosphere on microstructure of Nb-C alloyed layers were analyzed. The forming mechanism of the Nb-C alloyed layer was verified using first-principle calculation. The results reveal that the Nb-C alloyed layer is composed of NbC and Nb2C. An addition of niobium in TiAl accelerates the diffusion of carbon atoms in the Nb-alloyed layer, leading to a thicker alloyed layer with higher carbon content. The carbon concentration and diffusing depth increase with methane gas. First-principle calculation shows that the forming energy of Nb-C duplex-treated TiAl is lower than those of single carburized TiAl and Nb-alloyed TiAl.

Study of Fe3Al-Based Alloys by Internal Friction and 59Fe Radiotracer Diffusion Measurements

2005 ◽  
Vol 237-240 ◽  
pp. 1258-1263
Author(s):  
Tatiana S. Pavlova ◽  
S.B. Golovina ◽  
Sergiy V. Divinski ◽  
Igor S. Golovin
Keyword(s):  
Internal Friction ◽  
Vacancy Concentration ◽  
Vacancy Diffusion ◽  
Diffusion Study ◽  
Snoek Peak ◽  
Dissolved Carbon ◽  
Friction Measurements ◽  
Nb Alloying

Anelastic effects caused by carbon and vacancy diffusion in Fe3Al based alloys with and without strong carbide forming elements (Ti and Nb) are investigated by internal friction measurements. The decrease of the Snoek peak in Fe–26Al–2Ti and Fe–26Al–0.3Nb alloys with respect to the Fe–26Al alloy is related to a decrease in the amount of interstitially dissolved carbon (C). The so-called X peak, which is observed in the Fe–26Al alloy, also almost disappears after alloying. In order to elucidate the vacancy contribution to the origin of the X peak radiotracer measurements of 59Fe diffusion were performed. The results indicate that the change in the interstitially dissolved C concentration is the main reason of the observed changes in the X peak, although a certain influence of Ti and Nb alloying on the total vacancy concentration may be deduced from the diffusion study.

scholarly journals Reduction of the thermal conductivity of the thermoelectric material ScN by Nb alloying

2017 ◽  
Vol 122 (2) ◽  
pp. 025116 ◽  
Author(s):  
Nina Tureson ◽  
Ngo Van Nong ◽  
Daniele Fournier ◽  
Niraj Singh ◽  
Somnath Acharya ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Material ◽  
Nb Alloying
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