scholarly journals Surface Strengthening of High-Alloyed Martensitic Steel by Staged Nitriding

2021 ◽  
Vol 346 ◽  
pp. 02035
Author(s):  
Petr Bibikov ◽  
Larisa Petrova ◽  
Irina Belashova ◽  
Peter Demin
Keyword(s):  
Phase Composition ◽  
Impact Toughness ◽  
Final Stage ◽  
Martensitic Steel ◽  
Surface Strengthening ◽  
Gas Nitriding ◽  
Diffusion Layers

Gas nitriding processes with cyclical rotation of ammonia and ammonia/air atmospheres are suggested for surface strengthening of martensitic Cr-Ni-W-Mo-V steel. One-, two-, and three-staged processes were studied differing by gas atmospheres at the final stage of processes. Microstructure and phase composition of received diffusion layers were examined. Results of microhardness, wear and impact toughness tests are discussed in correspondence with the layers structure.

The effect of stadial nitrogenization on the structure and properties of martensitic steel 13X11N2V2MF

2021 ◽  
Vol 2021 (12) ◽  
pp. 12-19
Author(s):  
Mikhail Prokofev ◽  
Larisa Petrova ◽  
Irina Belashova ◽  
Petr Bibikov
Keyword(s):  
Wear Resistance ◽  
Martensitic Steel ◽  
New Method ◽  
Structure And Properties ◽  
High Quality ◽  
Corrosion Stability ◽  
Test Mode ◽  
Gas Nitriding ◽  
Diffusion Layers

A new method of gas nitriding is presented, which produces obtaining high-quality diffusion layers that meet the requirements of the use for various purposes, including aviation ones. Peculiar properties of highly alloyed martensitic steel nitriding after stadial thermo-gas-cyclic nitrogenization under partially dissociated ammonia with air additives have been examined. The results of metallographic studies, diagnostic leach, tests for wear resistance, impact hardness and corrosion stability, depending on the test mode are presented.

scholarly journals Nitriding of High Speed Steel for Improvement of Tools Resistance

2022 ◽  
Author(s):  
L. Petrova
Keyword(s):  
Phase Composition ◽  
High Speed ◽  
High Speed Steel ◽  
Dispersion Hardening ◽  
Internal Nitriding ◽  
High Quality ◽  
Gas Nitriding ◽  
Diffusion Layers ◽  
Tungsten Nitrides ◽  
Nitride Zone

Abstract. The article is devoted to the study of the gas nitriding process, which makes it possible to obtain high-quality diffusion layers in high-speed steel M2 on the basis of an internal nitriding zone without a brittle nitride zone. The results of studies of the nitrided steel phase composition with a change of the saturating atmosphere during dilution of ammonia by hydrogen are presented. An increase in the resistance of the nitrided tool when drilling structural steel is shown, which is associated with the dispersion hardening of the internal nitriding zone with tungsten nitrides.

The Effect of Heating on Phase Composition of the Cr3C2- Ti System Hard Alloys Fabricated by the Explosive Compaction of Powder Mixtures

2019 ◽  
Vol 945 ◽  
pp. 617-622 ◽  
Author(s):  
V.O. Kharlamov ◽  
Aleksandr Vasilevich Krokhalev ◽  
S.V. Kuz’min ◽  
V.I. Lysak
Keyword(s):  
Phase Composition ◽  
Chromium Carbide ◽  
Heating Temperature ◽  
Calculated Data ◽  
Fine Powder ◽  
Hard Alloys ◽  
Explosive Compaction ◽  
X Ray ◽  
Diffusion Layers ◽  
Equilibrium Phases

The article reports findings on theoretically-calculated data and experimental results obtained with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy methods of the analysis of hard alloys produced by the explosive compaction of the Cr3C2 chromium carbide powders with titanium, first in the original condition and then after heating to 1200 °C. It was established that when heated to 600 °С the phase composition of hard alloys does not change and corresponds to the composition of the original components of the powder mixture. When the heating temperature was increased to 650 °С, new fine powder fractions emerged at the “chromium carbide – titanium” interface. At the temperature of 700 °С two separate diffusion layers emerged and grew in the opposite directions. Due to this growth the source phases in the alloy fully disappeared at 1200 °С and two equilibrium phases were formed.

scholarly journals Effects of Various Corrosive Ions on Metakaolin Concrete

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1108
Author(s):  
Xupeng Chen ◽  
Zhuowen Sun ◽  
Jianyong Pang
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Magnesium Hydroxide ◽  
Final Stage ◽  
Interaction Mechanism ◽  
Physical And Mechanical Properties ◽  
Reciprocal Inhibition ◽  
Ion Content ◽  
Microstructural Changes ◽  
Concrete Corrosion

In order to study and verify if the three corrosive irons of SO42−, Mg2+, and Cl− could promote or inhibit each other in concrete corrosion as time goes by, we take Metakaolin (MK) as the research object to explore the interaction mechanism among ions by testing the physical and mechanical properties, the ion content, the phase composition, and the microstructural changes of the MK concrete under the action of various ion combinations. The results show that during the initial and middle stages of the corrosion (40–80 days), SO42− and Mg2+ are in reciprocal inhibition relation, Cl− could inhibit the action of SO42−, and Mg2+ could promote the diffusion of Cl−. However, at the final stage of corrosion (120 days), SO42− and Mg2+ could mutually promote each other, and both irons could promote the diffusion of Cl−. Mg2+ could mainly produce magnesium hydroxide and M-S-H inside the concrete, SO42− mainly generates the ettringite and gypsum, while Cl− mainly produces Friedel salt and NaCl crystal.

scholarly journals Microstructures and Properties of AlMgTi-Based Metal-Intermetallic Laminate Composites by Dual-Steps Vacuum Hot Pressing

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3932
Author(s):  
Linggang Meng ◽  
Bingwen Zhou ◽  
Bin Ya ◽  
Dong Jing ◽  
Yingxi Jiang ◽  
...  
Keyword(s):  
Phase Composition ◽  
Hot Pressing ◽  
Bending Strength ◽  
Laminated Composites ◽  
Laminate Composites ◽  
Transition Layers ◽  
Vacuum Hot Pressing ◽  
Microhardness Distribution ◽  
Specific Strength ◽  
Diffusion Layers

AlMgTi-based metal–intermetallic laminated composites were successfully fabricated through an innovative dual-step vacuum hot pressing. First, this study prepares the AlTi-based laminated composites by vacuum hot pressing at 650 °C. Then, the researchers place the Mg-Al-1Zn (AZ31) magnesium alloy between the prepared AlTi-based laminated composites at 430 °C for hot pressing. This study investigates the microstructure, phase composition, and microhardness distribution across interfaces of the intermetallics and metal. A multilayer phase (Mg17Al12, Al3Mg2, and transition layers) structure can be found from the diffusion layers between Al and AZ31. The microhardness of the material presents a wavy distribution in the direction perpendicular to the layers; the maximum can be up to 600.0 HV0.2 with a minimum of 28.7 HV0.2 The microhardness gradient of an AlMgTi-based composite is smoother due to the different microhardness of the layers, and reduces the interface stress concentration. The bending strength of AlMgTi-based composites can reach 265 MPa, and the specific strength is 105 × 103 Nm/kg, higher than AlTi-based composites.

Effect of Boron on Microstructure and Impact Toughness of a 10%Cr Martensitic Steel

2012 ◽  
Vol 706-709 ◽  
pp. 847-852 ◽  
Author(s):  
Nadezhda Dudova ◽  
Rustam Kaibyshev
Keyword(s):  
Impact Toughness ◽  
Prior Austenite ◽  
Martensitic Steel ◽  
Boron Segregation ◽  
Austenite Grains

It was shown that in a 10% Cr martensitic steel enriched by boron this element tends to segregate within M23C6 carbides having the film-like shape and precipitated on the boundaries of prior austenite grains (PAG), mainly. It leads to a low value of Charpy V-notch impact toughness of 6 J/cm2. These carbides are highly resistant against the spheroidizing. Only the tempering at 770°C leads to the final formation of M23C6 carbides having the equiaxed shape. Concurrently, this tempering strongly decreases boron segregation. As a result, the 10% Cr martensitic steel exhibits a high value of Charpy V-notch impact toughness of 260 J/cm2.

Phase composition of the diffusion layers of metallic coatings on heat-resistant nickel alloys

1994 ◽  
Vol 36 (12) ◽  
pp. 638-642
Author(s):  
E. N. Kablov ◽  
G. I. Morozova ◽  
G. N. Matveeva ◽  
S. A. Budinovskii
Keyword(s):  
Phase Composition ◽  
Nickel Alloys ◽  
Metallic Coatings ◽  
Heat Resistant ◽  
Diffusion Layers
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