scholarly journals Estratégias para o Desenvolvimento de Revestimentos Resistentes ao Desgaste: Uma Revisão

2021 ◽  
Vol 26 ◽  
Author(s):  
Giuseppe Pintaude
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Wear Resistance ◽  
Volume Fraction ◽  
Metallic Matrix ◽  
Intrinsic Property ◽  
Hard Phase ◽  
Hardness Increase ◽  
Dilution Level ◽  
Wear Tests

Abstract This review presents the possible strategies to increase the wear resistance of hardfacing alloys based on metallic matrix and second hard phase’s coupled design. As the wear resistance is not an intrinsic property of material, the results of many wear tests are discussed in light of the interaction between mechanical properties and wear severity, which is dependent on the microstructure. These strategies are based on the hardness increase, considering the kind and size of the second hard phase, the fracture toughness, and the dilution level of hardfacing. The guidelines provided for designing better the hardfacing alloys for usual abrasion conditions depending on the volume fraction of the second hard phase.

Microstructure and Mechanical Properties of Mo2FeB2 Based Cermets Containing SiC Whisker

2012 ◽  
Vol 625 ◽  
pp. 304-307 ◽  
Author(s):  
Hai Zhou Yu ◽  
Wen Jun Liu ◽  
Lian Ying ◽  
Min You
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Boundary ◽  
Grain Growth ◽  
Rupture Strength ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Hard Phase ◽  
Maximum Hardness ◽  
Vacuum Sintering

Four series of cermets with the SiC whisker content between 0 and 1.0 wt.% were prepared by vacuum sintering. The transverse rupture strength (TRS), hardness (HRA) and fracture toughness (KIC) were also measured. The SiC whiskeraddition was located at the grain boundaries, which prevented grain boundary migration and restrained the grain growth. However, an increasing SiC whisker content decreased the wettability of the binder on the Mo2FeB2 hard phase. The highest TRS and fracture toughness was found for the cermets with 0.5 wt.% SiC whisker addition, whereas the cermets without SiC whisker addition exhibited the maximum hardness.

Microstructure, Mechanical Properties, Sintering and Fracture Behavior of Ti(C, N) Based Cermets Granules/Ti(C, N) Based Cermets Composite

2020 ◽  
Vol 837 ◽  
pp. 139-145
Author(s):  
Ai Jun Liu ◽  
Gang Li ◽  
Ning Liu ◽  
Ke Bei Chen ◽  
Hai Dong Yang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Relative Density ◽  
Fracture Behavior ◽  
Rupture Strength ◽  
Binder Phase ◽  
Hard Phase ◽  
Opposite Trend ◽  
The Matrix ◽  
Sintering Properties

Effect of Ti (C,N) based cermets granule on the microstructure, mechanical properties, sintering and fracture behavior of Ti (C,N) based cermets was investigated. Results show that the Ti (C,N) based cermets granules distribute in the matrix homogeneously. A nanoindentation study was performed on hard phase and binder phase in the matrix and granule. With the increase of granules content, sintering properties is worse. With the increase of granules content, transverse rupture strength (TRS) and relative density decrease gradually, while the hardness has an opposite trend. The fracture toughness increases firstly with increasing granule, and then decreases with the further increase of granules. Higher fracture toughness of the cermets is mainly owing to the crack branch and higher fracture energy of coarse granule.

Effect of Ball-Milling Time on the Microstructure and Mechanical Properties of Submicron Ti(C,N)-Based Cermets

2013 ◽  
Vol 589-590 ◽  
pp. 584-589
Author(s):  
Hui Jun Zhou ◽  
Chuan Zhen Huang ◽  
Bin Zou ◽  
Han Lian Liu ◽  
Hong Tao Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Ball Milling ◽  
Milling Time ◽  
Rupture Strength ◽  
Submicron Particles ◽  
Titanium Carbonitride ◽  
Hard Phase ◽  
Ball Milling Time ◽  
Scanning Electron

In this study, titanium carbonitride (Ti(C,N)) based cermets were prepared by submicron particles, sintered in a vacuum and hot-pressing furnace. And the effect of different ball-milling time (36 h, 48 h, 60 h and 72 h, respectively, mostly aimed for mixing) on the mechanical properties of Ti(C,N)-based cermets, including transverse rupture strength (TRS), Vickers hardness (HV20), fracture toughness (KIC) and microstructure were investigated. The results showed that the TRS, hardness and fracture toughness were all improved with an increase in ball-milling time (not more than 60 h). Scanning electron microscopy (SEM) investigations on the microstructure of cermets with different ball-milling time revealed that the compound powders were not very well-distributed as a whole and there were coarse hard phase grains, but the microstructure was very homogeneous in parts, and the microstructure of cermets with a ball-milling time of 60 h is relatively more homogeneous. So a refinement to Ti(C,N) raw particles is needed in later studies.

Processing and Mechanical Properties of PM Processed Fe-Cu-Co Alloys

2008 ◽  
Vol 591-593 ◽  
pp. 247-251 ◽  
Author(s):  
A.P. Barbosa ◽  
L.J. Oliveira ◽  
Guerold Sergueevitch Bobrovinitchii ◽  
R.S. Guimarães ◽  
S. Crespo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Diamond Tools ◽  
Cu Alloys ◽  
Co Alloys ◽  
Wear Tests ◽  
The Ideal

In this work, a study to process and characterize Fe-Cu alloys with reduced Co content is shown. The Fe-Cu-Co alloys were processed by elemental blending of powders of the system Fe- 15%wtCu with various amounts of Co, pressing at 350MPa, and sintering at 1150°C/25min./10-2 mbar. The sintered microstructure was observed. It was conducted hardness and wear tests, aiming to define the ideal Cu addition for future use in impregnated diamond tools. It was observed that higher Co contents results in improved hardness and wear resistance in the studied Fe-Cu alloys.

Mechanical Properties of Transparent Polycrystalline Silicon Nitride

2006 ◽  
Vol 317-318 ◽  
pp. 305-308 ◽  
Author(s):  
Rak Joo Sung ◽  
Takafumi Kusunose ◽  
Tadachika Nakayama ◽  
Yoon Ho Kim ◽  
Tohru Sekino ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Nitride ◽  
Young’S Modulus ◽  
Fracture Strength ◽  
Polycrystalline Silicon ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Β Phase ◽  
Α Phase

A novel transparent polycrystalline silicon nitride was fabricated by hot-press sintering with MgO and AlN as additives. The mixed powder with 3 wt.% MgO and 9 wt.% AlN was sintered at 1900oC for 1 hour under 30 MPa pressure in a nitrogen gas atmosphere. Transparent polycrystalline silicon nitride was successfully fabricated. The mechanical properties such as density, hardness, young’s modulus, fracture strength and fracture toughness were evaluated. The effect of α/β phase on the mechanical properties of transparent polycrystalline silicon nitride was investigated. The properties were changed depending on the amount of α/β phase. The hardness and Young's modulus increased with increasing the volume fraction of α-phase fraction as a reflection of the higher hardness of α-phase Si3N4. The fracture toughness and fracture strength decreased with decreasing the volume fraction of β-phase Si3N4.

Development of VC-Ni Eutectic Alloys for Wear Resistance

2014 ◽  
Vol 1019 ◽  
pp. 347-354 ◽  
Author(s):  
O.A. Apata ◽  
T.N. Muobeleni ◽  
A.A. Fabuyide ◽  
E.N. Ogunmuyiwa ◽  
G.O. Rading ◽  
...  
Keyword(s):  
Solid Solution ◽  
Wear Resistance ◽  
Vanadium Carbide ◽  
Eutectic Alloys ◽  
Hard Phase ◽  
Corrosion Resistant ◽  
Wide Range ◽  
Vanadium Carbides ◽  
Co Alloys ◽  
Wear Tests

Vanadium carbide is less dense, harder and tougher than tungsten carbide, and nickel is more corrosion resistant that cobalt. Replacing the binder with Ni should improve the corrosion resistance. Since there are eutectics with a wide range of compositions in the C-Ni-V system, this system has potential for wear resistant alloys with ~VC as the discrete hard phase and the nickel solid solution as the binder. The aim of this work was to ascertain if eutectic microstructures with vanadium carbides could be beneficial to wear resistance. Phase studies confirmed the wide range of the eutectic alloys, with VC + (Ni), VC + σ′, VC + (V) and graphite + (Ni) and different morphologies. Preliminary wear tests showed results comparable to WC-Co alloys.

Effect of carbides on the wear resistance of white cast iron alloyed with 12.7 wt.-% Cr and nickel

2020 ◽  
Vol 62 (8) ◽  
pp. 788-792
Author(s):  
Tanju Teker ◽  
S. Osman Yilmaz ◽  
Tekirdağ Teker
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Cast Iron ◽  
White Cast Iron ◽  
Volume Fraction ◽  
High Wear Resistance ◽  
Homogeneous Distribution ◽  
Nickel Concentration ◽  
Carbide Size ◽  
Wear Tests

Abstract White cast iron with about 12.7 wt.-% chromium was alloyed with Ni, W and Mo for heat treatment applications. Heat treatments were performed at a range of 850-1050 °C for 1 h in order to distribute M7C3 carbides homogeneously in an environment of high wear resistance. The contents of the C, Cr, Ni, Mo, Mn and Si elements selected for the alloys were similar, though a 6 wt.-% nickel concentration was chosen. Microstructural changes in the specimens were examined by scanning electron microscopy (SEM) and optical microscopy (OM). Macro-hardness, average carbide size and volume fraction were analyzed. Wear tests were carried out under different loads of 10, 20 and 30 N. It was seen that heat treatment changed the carbide size and homogeneous distribution of the carbides. Moreover, the addition of nickel to HCrWCI increased fracture toughness and reduced the wear rate.

Mechanical Properties of Modified Polypropylene Coarse Fiber-Reinforced, High-Strength, Lightweight Concrete

2011 ◽  
Vol 374-377 ◽  
pp. 1499-1506
Author(s):  
Rong Hui Zhang ◽  
Jian Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
High Strength ◽  
Lightweight Aggregate Concrete ◽  
Fiber Reinforced ◽  
Fiber Volume

In this study, the effect of micro-expansion high strength grouting material (EGM) and Modified polypropylene coarse fiber (M-PP fiber) on the mechanical properties of lightweight concrete are investigated. The influence of EGM and M-PP fiber on compressive strength , flexural strength and drying shrinkage of concrete are researched, and flexural fracture toughness are calculated. Test results show that the effect of EGM and M-PP fiber volume fraction (Vf) on flexural strength and fracture toughness is extremely prominent, compressive strength is only slightly enhanced, and the rate of shrinkage is obviously decreased. It is observed that the shape of the descending branch of load-deflection and the ascending branch of shrinkage-age tends towards gently with the increase of Vf. And M-PP fiber reinforced lightweight aggregate concrete is more economical.

Effect of MnO on the microstructures, phase stability, and mechanical properties of ceria-partially-stabilized zirconia (Ce–TZP) and Ce–TZP–Al2O3 composites

1990 ◽  
Vol 5 (9) ◽  
pp. 1948-1957 ◽  
Author(s):  
J. S. Wang ◽  
J. F. Tsai ◽  
D. K. Shetty ◽  
A. V. Virkar
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Growth ◽  
Phase Stability ◽  
Volume Fraction ◽  
Transformation Toughening ◽  
Composite Ceramics ◽  
Four Point Bending ◽  
Crack Tips ◽  
The Stability

The effects of increasing amounts of MnO additions on the microstructures, phase stability, and mechanical properties of ZrO2–12 mol % CeO2 and ZrO2–12 mol% CeO2–10 wt.% Al2O3 were studied. MnO suppressed grain growth in ZrO2–12 mol% CeO2, while enhancing the mechanical properties significantly (strength = 557 MPa, fracture toughness = 9.3 MPa at 0.2 wt.% MnO). The enhanced mechanical properties were achieved despite an increased stability of the tetragonal phase, as evidenced by a lower burst transformation temperature (Mb) and a reduced volume fraction of the monoclinic phase on the fracture surface. In ZrO2–12 mol% CeO2–10 wt.% Al2O3, the addition of MnO suppressed the grain size of ZrO2, while promoting grain growth and changing the morphology of Al2O3. More significantly, the stability of the tetragonal ZrO2 phase decreased (high Mb temperature) with a concurrent increase in fracture toughness (13.2 MPa at 2 wt.% MnO) and transformation plasticity (1.2% in four-point bending). The widths of the transformation zones observed adjacent to the fracture surfaces showed a consistent inverse relation to the transformation yield stress, as would be expected from the mechanics of stress-induced phase transformation at crack tips. The improvements in mechanical properties obtained in the base Ce–TZP and the Ce–TZP–Al2O3 composite ceramics with the addition of MnO are critically examined in the context of transformation toughening and other possible mechanisms.

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