scholarly journals WEAR RESISTANCE OF Al–12 WT.% Si REINFORCED WITH NbC PARTICLES BY LASER CLADDING

Author(s):  
M. Lopes ◽  
A. Ramalho ◽  
R. Anandkumar ◽  
A. Almeida ◽  
R. Vilar ◽  
...  

Al12Si–NbC composite coatings were deposited by laser cladding on a substrate of Al–7Si alloy. The microstructure and wear resistance of the coatings were evaluated in comparison to the properties of the substrate and the matrix alloy. The wear resistance was evaluated using ball-on-plate reciprocating sliding tests using an AISI 52100 steel sphere as counterbody. The coatings microstructure consists of NbC particles dispersed in a matrix of α–Al and α–Al/Si eutectic. The reinforcement with NbC particles induces a considerable increase in the average hardness of the matrix material from 85±1 HV to 147±40 HV and in the respective wear resistance. The wear mechanisms involve oxidation, adhesion with plastic deformation and delamination.

2017 ◽  
Vol 24 (4) ◽  
pp. 541-546 ◽  
Author(s):  
Hongxia Zhang ◽  
Huijun Yu ◽  
Chuanzhong Chen

AbstractThe composite coatings were fabricated by laser cladding Ni60A/B4C pre-placed powders on the surface of Ti-6Al-4V alloy for improving wear resistance and hardness of the substrate. In this research, the composite coatings were studied by means of X-ray diffraction, scanning electron microscope and energy dispersive spectrometer. The sliding wear tests were performed using MM200 wear test machine. The hardness of the coatings was tested by HV-1000 hardness tester. After laser cladding, it was found that there was a good metallurgical bond between the laser cladding coating and Ti-6Al-4V substrate. The composite coatings were mainly composed of the matrix of γ-Ni and a little Ni3Ti and the reinforcements of TiB2, TiC and CrB. The hardness of the sample of Ni60A-5B4C was approximately 2.5–3.5 times that of the Ti-6Al-4V substrate. The hardness of the sample of Ni60A-10B4C was 30% higher than that of sample 1. The wear resistance of samples 1 and 2 were 11 times and 10 times that of the substrate, respectively.


2015 ◽  
Vol 22 (03) ◽  
pp. 1550044 ◽  
Author(s):  
H. X. ZHANG ◽  
H. J. YU ◽  
C. Z. CHEN

The composite coatings were fabricated by laser cladding Al / TiN pre-placed powders on Ti –6 Al –4 V substrate for enhancing wear resistance and hardness of the substrate. The composite coatings were analyzed by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The sliding wear tests were performed by MM200 wear test machine. The hardness of the coatings was tested by HV-1000 hardness tester. After laser cladding, it was found that there was a good metallurgical bond between the coating and the substrate. The composite coatings were mainly composed of the matrix of β- Ti  ( Al ) and the reinforcements of titanium nitride ( TiN ), Ti 3 Al , TiAl and Al 3 Ti . The hardness and wear resistance of the coatings on four samples were greatly improved, among which sample 4 exhibited the highest hardness and best wear resistance. The hardness of the coating on sample 4 was approximately 2.5 times of the Ti –6 Al –4 V substrate. And the wear resistance of sample 4 was four times of the substrate.


2021 ◽  
Author(s):  
Linlin ZHANG ◽  
Dawei ZHANG

Ni-Co-W composite coatings modified by different contents of Co-based alloy powder in the Ni-based alloy with 35 wt.% WC (Ni35WC) were deposited on stainless steel by laser cladding. The influence of compositional and microstructural modification on the wear properties has been comparatively investigated by XRD, SEM, and EDS techniques. It was found that the austenite dendrites in the modified coating adding 50 wt.% Co-based alloy were refined and a lot of Cr23C6 or M23(C, B)6 compounds with fine lamellar feature were formed around austenitic grain boundaries or in the intergranular regions. The contribution of element Co to the modification of Ni35WC coating is that it cannot only promote the formation of more hard compounds to refine austenite grains, but also refine the size of precipitates, and change the phase type of eutectic structure as a result of disappeared Cr boride brittle phases. A noticeable improvement in wear resistance is obtained in the Ni35WC coating with 50 wt.% Co-based alloy, which makes the wear rate decreased by about 53 % and 30% by comparison to that of the substrate and the Ni35WC coating, respectively. It is suggested that the improvement is closely related to the composite coating being strengthened owing to the increase of coating hardness, formation of a fine-grained microstructure caused by Co, and fine hard precipitate phases in the eutectic structure.


Author(s):  
V. A. Kalinichenko ◽  
A. S. Kalinichenko ◽  
S. V. Grigoriev

To create friction pairs operating in severe working conditions, composite materials are now increasingly used. Composite materials obtained with the use of casting technologies are of interest due to the possibility to manufacture wide range of compositions at low price compared to powder metallurgy. Despite the fact that many composite materials have been sufficiently studied, it is of interest to develop new areas of application and give them the properties required by the consumer. In the present work the composite materials on the basis of silumin reinforced with copper granules were considered. Attention was paid to the interaction between the matrix alloy and the reinforcing phase material as determining the properties of the composite material. The analysis of distribution of the basic alloying elements in volume of composite material and also in zones of the interphases interaction is carried out. The analysis of the possibility of obtaining a strong interphase zone of contact between the reinforcing component and the matrix material without significant dissolution of the reinforcing material is carried out.


Author(s):  
M. Shettar ◽  
P. Hiremath ◽  
G. Shankar ◽  
A. Kini ◽  
S. Sharma

The current work focuses on enhancing wear resistance due to the presence of reinforcements and the effect of ageing treatment on hybrid composites of Al6061-SiC+B4C. By varying weight percentage, two kinds of reinforcements, viz. silicon carbide and boron carbide, were prepared for hybrid composites by the liquid state process known as the method of stir casting. The solutionising temperature of 550 °C for 2 hours and ageing temperature of 100-200°C at different time intervals were used for both Al6061 alloy and its composites during heat treatment. Microstructural and mechanical characterisation were carried out using a standard testing procedure. Compared to Al6061 matrix alloy, artificially peak aged composites show 100-140% improvement in hardness due to harder reinforcements and precipitation of solute rich secondary phases during ageing treatment. Overall, an 80-100% increase in wear resistance observed during peak ageing of hybrid composites. Analysis of Al6061 matrix alloy wear out surface shows extensive grooving and ploughing of the surface with the matrix material smear at many spots. The presence of tribolayer in Al6061-SiC+B4C composites shows a smoother surface than the Al6061 matrix alloy, which results in an excellent lubrication effect during an improvement in wear resistance. The wear surface of base aluminium alloy doesn’t show the existence of iron in the tribolayer. The research work is significant in forming a thermally activated wear-resistant metallic tribolayer with good tribological properties.


2016 ◽  
Vol 254 ◽  
pp. 290-295
Author(s):  
Iosif Hulka ◽  
Ion Dragoş Uţu ◽  
Viorel Aurel Şerban ◽  
Alexandru Pascu ◽  
Ionut Claudiu Roată

Laser cladding process is used to obtain protective coatings using as heat source a laser. This melts the substrate and the feedstock material to create a protective coating and provides a strong metallurgical bond with minimal dilution of the base material and reduced heat affected zone. In the present study a commercial NiCrSiFeB composition was deposited by laser cladding process using different parameters onto the surface of a steel substrate. The obtained coatings were investigated in terms of microstructure, hardness and wear behavior. The experimental results revealed that the laser power had a considerable influence on the wear resistance of NiCrSiFeB coatings.


2011 ◽  
Vol 314-316 ◽  
pp. 143-146
Author(s):  
Xin Feng ◽  
Yan Qiu Xia

AISI 1045 steels were laser-clad with Ni-based powder by CO2 HJ-4 coherent laser. The phase composition of the laser-cladding coating was investigated by means of X-ray diffraction (XRD). The cross-section of the cladding coating was observed using a scanning electron microscopy (SEM). The friction and wear properties of the laser cladding coatings sliding against AISI 52100 steel under the lubrication of liquid paraffin containing various anti-wear and extreme pressure additives were investigated using an Optimol SRV reciprocating motion friction and wear tester. Results showed that the laser-cladding coating considerably decreased coefficient of friction and increased wear resistance in sliding against AISI 52100 steel and attributed to the change in the hardness, phase composition of the laser-cladding coating and tribochemical reactions between the laser-cladding coating and the extreme pressure and anti-wear additives.


Materials ◽  
2003 ◽  
Author(s):  
Michael H. Santare ◽  
Wenzhong Tang ◽  
John E. Novotny ◽  
Suresh G. Advani

High-density polyethylene (HDPE) was used as the matrix material for a carbon nanotube (CNT) polymer composites. Multi-wall carbon nanotube composite films were fabricated using the melt processing method. Composite samples with 0%, 1%, 3% and 5% nanotube content by weight were tested. The mechanical properties of the films were measured by the small punch test and wear resistance was measured with a block-on-ring wear tester. Results show increases in the stiffness, peak load, work-to-failure and wear resistance with increasing nanotube content.


2020 ◽  
pp. 2050046
Author(s):  
TIANWEI YANG ◽  
ZHAOHUI WANG ◽  
SHIHAI TAN ◽  
FU GUO

To increase the strength and wear resistance of material surfaces, various combinations of B4C and 80TiFe powder were mixed into a Fe60 self-fluxing alloy powder; the composite coatings reinforced by TiB2–TiC were successfully prepared on Q235 steel surfaces by laser cladding. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to study the microstructure and chemical and phase composition. Microhardness and wear testers were used to investigate the mechanical properties. The results show that the interfaces of composite coatings and substrate materials are excellent for metallurgical bonding. The block-like TiB2 particles and flower-like TiC particles are uniformly distributed in the cladding coating. When the mass fraction of the mixed powder is 30%, the average microhardness of the coating is approximately 1100 HV[Formula: see text], which is 50% higher than that without the mixed powder, and demonstrates the best wear with a performance twice as better as that of the substrate.


Photonics ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 127
Author(s):  
Yury Korobov ◽  
Yulia Khudorozhkova ◽  
Holger Hillig ◽  
Alexander Vopneruk ◽  
Aleksandr Kotelnikov ◽  
...  

Ni/60WC coatings on copper substrate were placed via laser deposition (LD). A structural study was conducted using electron microscopy and a microhardness evaluation. Two body abrasive wear tests were conducted with a pin-on-plate reciprocating technique. A tool steel X12MF GOST 5960 (C-Cr-Mo-V 1.6-12-0.5-0.2) with a hardness of 63 HRC was used as a counterpart. The following results were obtained: Precipitation of the secondary carbides takes place in the thicker layers. Their hardness is lower than that of the primary carbides in the deposition (2425 HV vs. 2757 HV) because they mix with the matrix material. In the thin layers, precipitation is restricted due to a higher cooling rate. For both LD coatings, the carbide’s hardness increases compared to the initial mono-tungsten carbide (WC)-containing powder (2756 HV vs. 2200 HV). Such a high level of microhardness reflects the combined influence of a low level of thermal destruction of carbides during laser deposition and the formation of a boride-strengthening phase from the matrix powder. The thicker layer showed a higher wear resistance; weight loss was 20% lower. The changes in the thickness of the laser deposited Ni-WC coating altered its structure and wear resistance.


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