scholarly journals Investigation of microstructural damage to eutectic carbides from scratch tests of a heat-treated Fe–Cr–W–Mo–V–C alloy

Wear ◽  
2016 ◽  
Vol 358-359 ◽  
pp. 137-147 ◽  
Author(s):  
Jing Guo ◽  
Yunli Feng ◽  
Ligang Liu ◽  
Xiaolei Xing ◽  
Xuejun Ren ◽  
...  
Keyword(s):  
Eutectic Carbides ◽  
Microstructural Damage ◽  
Heat Treated ◽  
Scratch Tests

scholarly journals Microstructure Evolution and Nanotribological Properties of Different Heat-Treated AISI 420 Stainless Steels after Proton Irradiation

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1736 ◽  
Author(s):  
L.Y. Dai ◽  
G.Y. Niu ◽  
M.Z. Ma
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Proton Irradiation ◽  
Energy Proton ◽  
Aisi 420 ◽  
Transmission Electron ◽  
Heat Treated ◽  
Nanoscale Friction ◽  
Scratch Tests

In this paper, low-energy proton irradiation experiments with different cumulative fluences were performed on samples of AISI 420 stainless steel that were either annealed or tempered at 600 or 700 °C. The effects of the cumulative proton irradiation fluence on the evolution of the microstructure of AISI 420 were studied by transmission electron microscopy (TEM). Scratch tests were performed using a Tribo Indenter nanomechanical tester, in order to investigate the effects of the cumulative fluence on the tribological properties of the AISI 420 stainless steel. The results indicate that the dislocation density of the microstructure near the surface of the AISI 420 stainless steel increases with higher cumulative proton irradiation fluences. Under the same load, the nanoscale friction coefficient and wear rate both decreased with increasing cumulative proton irradiation fluence. This indicates that the surface hardening effect induced by proton irradiation can diminish the nanoscale friction coefficient and wear rate.

Influence of Processing Parameters on the Local Scratch Resistance of Cold Sprayed Ti6Al4V Coatings

2019 ◽  
Vol 813 ◽  
pp. 92-97
Author(s):  
Paloma Sirvent ◽  
Miguel Ángel Garrido-Maneiro ◽  
Pedro Poza
Keyword(s):  
Wear Rate ◽  
Abrasion Resistance ◽  
Normal Load ◽  
Processing Parameters ◽  
Scratch Resistance ◽  
Gas Temperature ◽  
Bulk Alloy ◽  
Heat Treated ◽  
Bulk Substrate ◽  
Scratch Tests

Ti6Al4V coatings were cold sprayed onto the same bulk alloy at standard conditions, using 800 °C as gas temperature, and a set of new conditions, using 1100°C as gas temperature, which improved coatings performance. Some of these coatings, processed with innovative parameters, were heat treated to promote adhesion and reduce porosity. Scratch tests were performed using a nanoindenter Agilent G200 and the effect of both normal load and scratch velocity were explored. The different mechanisms responsible of wear were evaluated, identifying ploughing and cutting as the main abrasion mechanisms. The wear rate measured in the standard coating was the highest, indicating that this material could not be used to repair the bulk component. However, the abrasion resistance measured in the coatings sprayed at 1100°C was similar to that found in the bulk substrate. Therefore, cold spray could be used for repairing using the new conditions evaluated in this work.

Influence of Heat Treatment of High-Speed Steel on its Microstructure, Hardness and Fracture Toughness

2013 ◽  
Vol 592-593 ◽  
pp. 680-683
Author(s):  
Franjo Cajner ◽  
Vojteh Leskovšek ◽  
Dragan Pustaić
Keyword(s):  
Fracture Toughness ◽  
High Speed ◽  
Volume Fraction ◽  
High Speed Steel ◽  
Experimental Investigations ◽  
Eutectic Carbides ◽  
Microstructural Parameters ◽  
Heat Treated ◽  
The Matrix ◽  
Steel Aisi

The correlation between fracture toughness, hardness and microstructure of vacuum heat-treated high-speed steel AISI M2 was investigated. Our intention was to investigate the influence of microstructural parameters such as the volume fraction of undissolved eutectic carbides, their mean diameter, the mean distance between the carbides, as well as the volume fraction of retained austenite in the matrix, on the above mentioned mechanical and fracture properties. The experimental investigations were performed on the high-speed steel. This steel had the following chemical composition (mass content in %): 0.89% C, 0.20% Si, 0.26% Mn, 0.027% P, 0.001% S, 3.91% Cr, 4.74% Mo, 1.74% V and 6.10% W.

scholarly journals Nanomechanical Behavior, Adhesion and Corrosion Resistance of Hydroxyapatite Coatings for Orthopedic Implant Applications

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 477
Author(s):  
Kaouther Khlifi ◽  
Hafedh Dhiflaoui ◽  
Amir Ben Rhouma ◽  
Joël Faure ◽  
Hicham Benhayoune ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
X Ray Diffraction ◽  
Homogeneous Microstructure ◽  
X Ray ◽  
Hydroxyapatite Coatings ◽  
Adhesion Behavior ◽  
Heat Treated ◽  
Before And After ◽  
Scratch Tests

The aim of this work was to investigate the nanomechanical, adhesion and corrosion resistance of hydroxyapatite (HAP) coatings. The electrodeposition process was used to elaborate the HAP coatings on Ti6Al4V alloy. The effect of hydrogen peroxide concentration H2O2 on the electrolyte and the heat treatment was studied. Surface morphology of HAP coatings was assessed, before and after heat treatment, by scanning electron microscopy associated with X-ray microanalysis (SEM-EDXS). Moreover, X-ray diffraction (XRD) was performed to identify the coatings’ phases and composition. Nanoindentation and scratch tests were performed for nanomechanical and adhesion behavior analysis. The corrosion resistance of the uncoated, the as-deposited, and the heat-treated coatings was investigated by electrochemical test. The obtained results revealed that, with 9% of H2O2 and after heat treatment, the HAP film exhibited a compact and homogeneous microstructure. The film also showed a crystal growth: stoichiometric hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP). After heat treatment, the nanomechanical properties (H, E) were increased from 117 ± 7 MPa and 24 ± 1 GPa to 171 ± 10 MPa and 38 ± 1.5 GPa respectively. Critical loads (LC1, LC2, and LC3) were increased from 0.78 ± 0.04, 1.6 ± 0.01, and 4 ± 0.23 N to 1.45 ± 0.08, 2.46 ± 0.14, and 4.35 ± 0.25 N (respectively). Furthermore, the adhesion strength increased from 8 to 13 MPa after heat treatment. The HAP heat-treated samples showed higher corrosion resistance (Rp = 65.85 kΩ/cm2; Icorr = 0.63 µA/cm2; Ecorr = −167 mV/ECS) compared to as-deposited and uncoated samples.

Effect of Sequential Helium and Nickel Ion Implantation on the Nano-Indentation Hardness of X750 Alloy

2020 ◽  
Author(s):  
Maisaa Tawfeeq ◽  
Robert Klassen
Keyword(s):  
Total Hardness ◽  
Indentation Hardness ◽  
Nickel Ion ◽  
Helium Bubbles ◽  
Defect Clusters ◽  
Microstructural Damage ◽  
Heat Treated ◽  
Clear Increase ◽  
Hardness Values ◽  
Inconel X750

Abstract Sequential He+ and Ni+ implantations were performed to investigate their combined effect on the indentation hardness of heat-treated Inconel X750 alloy. The microstructure of the ion-implanted region was also characterized with TEM. The alloy displayed a pronounced softening with very low Ni+ implantation levels, ? = 0.01 - 1.0 dpa, however it showed a clear increase in hardness when implanted with He+ up to CHe = 5000 appm. Samples subjected to sequential He+ and Ni+ implantations displayed hardness values between those presented by sole He+ or Ni+ implantation suggesting that the effects of ion-induced microstructural damage and helium accumulation on the hardness of this alloy can be considered as independent and additive over the range of conditions studied. This observation is in contradiction to previously reported TEM studies which suggest that accumulated helium slows the dissolution/disordering of the ?' hardening phase in this alloy. In our study, established theories were applied to assess the contribution of ion-induced defect clustering, ?' precipitate disordering, and helium bubble accumulation to the hardness of the X750 alloy. It was observed that generation of ion-induced defect clusters and the formation of helium bubbles increased the indentation hardness slightly while the disordering of ?' precipitates resulted in a dramatic decrease in the total hardness. Ni+ and He+ implantation also had different effects on the depth dependence of the indentation hardness (ISE). ISE was pronounced in the samples subjected to Ni+ implantation while it was almost absent in samples subjected to He+.

scholarly journals Grinding and Abrasive Wear

1970 ◽  
Vol 185 (1) ◽  
pp. 537-551 ◽  
Author(s):  
T. C. Buttery ◽  
J. F. Archard
Keyword(s):  
Abrasive Wear ◽  
Microscopic Examination ◽  
Grinding Forces ◽  
Heat Treated ◽  
Scratch Tests ◽  
The Relationship ◽  
Wear Tests ◽  
Worn Surfaces

To explore the relationship between grinding and abrasive wear, a range of differing experiments has been performed. These include simple wear tests, dynamometer measurements of grinding forces, simple scratch tests with both idealized indentors and abrasive grits, and the microscopic examination of abrasive wheels and worn surfaces of steel. It is suggested that grinding and abrasive wear should be regarded as essentially similar mechanisms. The anomalies which occur with heat-treated steels, of a range of hardness, in both grinding and abrasive wear may be attributable to the influence of ploughing which affects the efficiency of the action of individual grits.

Microstructures and Cohesiveness of Alkali- and Heat-Treated Films on a Ti-15Zr-4Nb-4Ta Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 3706-3711
Author(s):  
Sengo Kobayashi ◽  
Koji Murakami ◽  
Kiyomichi Nakai ◽  
Makoto Hino
Keyword(s):  
Heat Treatment ◽  
Electron Spectroscopy ◽  
Alkali Treatment ◽  
Sodium Titanate ◽  
X Ray Diffraction ◽  
Compositional Gradient ◽  
X Ray ◽  
Heat Treated ◽  
Naoh Solution ◽  
Scratch Tests

Microstructures of alkali- and/or heat-treated films on a Ti-15Zr-4Nb-4Ta alloy were analyzed by means of scanning electron microscopy, thin film X-ray diffraction and Auger electron spectroscopy. The cohesiveness of films was also evaluated by scratch tests. The films were formed by immersion in 5M aqueous NaOH solution at 60 °C for 86.4 ks (alkali treatment) followed by heating at 400–600 °C for 3.6 ks. The film on alloy formed by alkali treatment exhibits the same strucutre as that formed on an alkali-treated titanium. Compositional gradient of alloying elements, Zr, Nb and Ta, is detected in the film. The cohesion of alkali-treated film is considerably increased by the heat treatment, and the maximum cohesion is obtained by heating at 600 °C. The increase in cohesion of alkali-treated film by heat treatment is due to both the diffusion of Zr into film and the formation of sodium titanate on substrate.

Development of High-Speed Steels for Cast Metal-Cutting Tools

2006 ◽  
Vol 113 ◽  
pp. 559-564 ◽  
Author(s):  
Alexander S. Chaus ◽  
J. Chovanec ◽  
M. Legerská
Keyword(s):  
Impact Toughness ◽  
High Speed ◽  
Metal Cutting ◽  
Cutting Tools ◽  
High Speed Steel ◽  
Eutectic Carbides ◽  
Alloying System ◽  
Heat Treated ◽  
Similar Chemical ◽  
The Impact

As-cast high-speed steels heat-treated have completely much lower impact toughness than that of the steels of a similar chemical composition but undergone hot working – rolling or forging. That is attributed to the influence of eutectic carbides, which especially being coarse, provide easily brittle intergrain fracture sites under low stress intensity factor levels. This is especially real for cast cutting tools. In order to exhibit good all-round performance the impact toughness enhancement of as-cast high-speed steels is obligatorily needed. In this connection it is expedient to turn from high-speed steels of conventional ledeburitic origin to high-speed steels of hypereutectoid and ferritic-carbidic ones with considerably lower carbide heterogeneity resulting in enhanced impact toughness. In the present work special features of the structure, phase composition and properties of such high-speed steels designed for cast tool are studied. In order to substitute tungsten by chromium in as-cast high-speed steel a special alloying system has also been developed.

Direct Observation of Crystalline Ordering In Naturally Graphitized Carbon Produced by Low Grade Metamorphism

1977 ◽  
Vol 35 ◽  
pp. 162-163
Author(s):  
Thomas R. McKee ◽  
Peter R. Buseck
Keyword(s):  
Crystallite Size ◽  
Sedimentary Rocks ◽  
Carbonaceous Material ◽  
Low Grade ◽  
X Ray ◽  
Graphitized Carbon ◽  
Transmission Electron ◽  
Heat Treated ◽  
Commercial Carbon ◽  
Metamorphic Zone

Sediments commonly contain organic material which appears as refractory carbonaceous material in metamorphosed sedimentary rocks. Grew and others have shown that relative carbon content, crystallite size, X-ray crystallinity and development of well-ordered graphite crystal structure of the carbonaceous material increases with increasing metamorphic grade. The graphitization process is irreversible and appears to be continous from the amorphous to the completely graphitized stage. The most dramatic chemical and crystallographic changes take place within the chlorite metamorphic zone.The detailed X-ray investigation of crystallite size and crystalline ordering is complex and can best be investigated by other means such as high resolution transmission electron microscopy (HRTEM). The natural graphitization series is similar to that for heat-treated commercial carbon blacks, which have been successfully studied by HRTEM (Ban and others).

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