Microstructures and Properties of Laser Cladding Composite Coating of Nano-Y2O3/Co-Based Alloys

2011 ◽  
Vol 295-297 ◽  
pp. 1315-1318
Author(s):  
Shang Lei Yang ◽  
Feng Guang Hu ◽  
Qing Lin Lin

By using laser cladding technology, a nano-Y2O3/Co-based composite coating was prepared in the Ni-based alloys substrate with Nano-Y2O3 and cobalt based alloys powder. The microstructure, micro-hardness wear resistance of the composite coating were researched by scanning electron microscopy (SEM) and other testing methods. The results show that the micro-hardness of laser cladding is HV868, and the welded surfacing layer is only HV512. Wearing values are decreased by 25.6 mg of the surfacing layer to 0.5 mg of the laser cladding layer in the wear testing of 40 minutes. The wear resistance of laser cladding layer is 51 times of the the wear resistance of the surfacing layer using the Co-28Cr-4W-1C electrode. The microstructure of laser cladding layer consists of the fusion zone, the fine equiaxed dendrite zone and the coarse crystalline zone.

2009 ◽  
Vol 41 (2) ◽  
pp. 199-207 ◽  
Author(s):  
X. Dong ◽  
J. Hu ◽  
Z. Huang ◽  
H. Wang ◽  
R. Gao ◽  
...  

In this study, the boronized layers were formed on the surfaces of specimens with a composition of Fe-2 wt. % Cu-0.4 wt. % C by sintering and boronizing simultaneously, using a pack boronizing method. The processes were performed in the temperature range of 1050 - 1150 oC at a holding time of 4 hours in 97 % N2 and 3 % H2 atmosphere. Scanning electron microscopy examinations showed that the boronized layers formed on the surface of boronized and sintered specimens have a denticular morphology. The thicknesses of the boronized layers varied from 63 to 208 ?m depending on the processing temperature. The structures of the boronized layers were Fe2B and FeB confirmed by X-ray diffraction analysis. The microhardness values of boronized layers ranged from 1360 to 2066 HV0.3 much higher than that of substrate hardness which was about 186 HV0.3. Wear testing results showed that the wear resistance of the boronized and sintered specimens was significantly improved, resulting from increased surface microhardness.


2012 ◽  
Vol 19 (02) ◽  
pp. 1250009 ◽  
Author(s):  
PENG LIU ◽  
WEI GUO ◽  
DAKUI HU ◽  
HUI LUO ◽  
YUANBIN ZHANG

The synthesis of hard composite coating on titanium alloy by laser cladding of Al/Fe/Ni+C/Si3N4 pre-placed powders has been investigated in detail. SEM result indicated that a composite coating with metallurgical joint to the substrate was formed. XRD result indicated that the composite coating mainly consisted of γ- (Fe, Ni) , FeAl , Ti3Al , TiC , TiNi , TiC0.3N0.7 , Ti2N , SiC , Ti5Si3 and TiNi . Compared with Ti-3Al-2V substrate, an improvement of the micro-hardness and the wear resistance was observed for this composite coating.


2011 ◽  
Vol 189-193 ◽  
pp. 830-833
Author(s):  
Yong Tao Zhao ◽  
Wen Xue Li ◽  
Jun Wei Zhou

The laser cladding of Fe power technology was used to repair worn plunger piston surface. The microstructure of cladding layer, binder course and the matrix were observed by OM and SEM. Besides, the micro-hardness of different zones was measured through micro-hardness testing. The results show that the matrix metal microstructure of plunger piston is made of ferrite and austenite. By laser cladding Fe-based power on base metal, the cladding layer grain is fine and uniform, grain growth has obvious direction and finally become dendrites oriented, the microstructure of cladding layer is both second-phase hard particles and Fe-based solutes. The combination between matrix and cladding layer is smooth, belong to metallurgy bonding. The hardness of cladding layer is higher than that of other parts in three parts, the max value of micro-hardness is about 1250HV, it can agree with wear resistance need of plunge piston surface.


2012 ◽  
Vol 531-532 ◽  
pp. 208-211
Author(s):  
Hong Ye ◽  
Shi Xin Peng ◽  
Zhong Lin Yan ◽  
Xiao Bin Zhang

The mixed powders of 70%Fe and 30%Al were precoated, and Fe-Al intermetallics coatings were produced on an aluminum ZL114A alloy by means of laser cladding. The microstructure and hardness of the coatings are analyzed by using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and microhardness testing machines. The results show that a fine surface quality can be obtained under a suitable process parameter of laser. The laser cladding layers are mainly consisted of phases of FeAl3, Fe3Al, FeAl with lump-like, granular, equiaxial and needle-like. The highest microhardness of the cladding layer achieved HV614 and raised 5~6 times in comparison to substrate.


2011 ◽  
Vol 18 (03n04) ◽  
pp. 103-108 ◽  
Author(s):  
JIANING LI ◽  
CHUANZHONG CHEN ◽  
CUIFANG ZHANG

Laser cladding of the Fe3Al + B4C/TiN + Al2O3 pre-placed powders on the Ti-6Al-4V alloy can form the Ti3Al/Fe3Al + TiN/TiB2 composite coating, which improved the wear resistance of the Ti-6Al-4V alloy surface. In this study, the Ti3Al/Fe3Al + TiN/TiB2 composite coating has been researched by means of X-ray diffraction and scanning electron microscope. It was found that during the laser cladding process, Al2O3 can react with TiB2 , leading to the formations of Ti3Al and B . This principle can be used to improve the Fe3Al + B4C/TiN laser-cladded coating on the Ti-6Al-4V alloy. Furthermore, during the cladding process, C consumed the oxygen in Fe3Al + B4C /TiN + Al2O3 molten pool, which retarded the productions of the redundant metal oxides.


2019 ◽  
Vol 26 (06) ◽  
pp. 1850207 ◽  
Author(s):  
XUELONG PING ◽  
SHUTING SUN ◽  
FENG WANG ◽  
HANGUANG FU ◽  
JIAN LIN ◽  
...  

In this paper, the enhancement of NiCrBSi coatings by adding Cr3C2 were investigated. The NiCrBSi coatings with different additions of Cr3C2 were produced by laser cladding. The microstructure, hardness and wear resistance of the coatings were studied by optical microscope (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), microhardness tester and M-200 wear tester. It is found that the main phases in the coatings are [Formula: see text]-Ni, Cr[Formula: see text]C6 and Cr7C3, and they also contain a small amount of CrB, Ni4B3 and Ni3Si2. Moreover, with the increase of Cr3C2 addition, the microhardness and wear resistance of coatings are obviously improved. When the addition of Cr3C2 is 20%, the wear resistance of the coating is the best, and the wear resistance of the coating increased by 191.2% than that of the Cr3C2-free coating. The wear resistance of coating decreases when the addition of Cr3C2 reaches 30%.


Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 793 ◽  
Author(s):  
Guofu Lian ◽  
Hao Zhang ◽  
Yang Zhang ◽  
Mingpu Yao ◽  
Xu Huang ◽  
...  

The influence of processing parameters on the micro-hardness and wear resistance of a Ni-based alloy and titanium carbide (TiC) composite cladding layer was studied. Mathematical models were developed to predict the micro-hardness and wear resistance of the cladding layer by controlling the laser cladding processing parameters. Key processing parameters were the laser power, scanning speed, gas flow, and TiC powder ratio. The models were validated by analysis of variance and parameter optimization. Results show that the micro-hardness is positively correlated with laser power and TiC powder ratio, where the TiC powder ratio shows the most significant impact. The wear volume decreased with an increasing TiC powder ratio. The targets for the processing parameter optimization were set to 62 HRC for micro-hardness and a minimal volume wear. The difference between the model prediction value and experimental validation result for micro-hardness and wear volume were 1.87% and 6.33%, respectively. These models provide guidance to optimize the processing parameters to achieve a desired micro-hardness and maximize wear resistance in a composite cladding layer.


2020 ◽  
Vol 10 (9) ◽  
pp. 3167 ◽  
Author(s):  
Guofu Lian ◽  
Chenmin Zhao ◽  
Yang Zhang ◽  
Meiyan Feng ◽  
Jibin Jiang

In order to improve the performance of the cladding layer, this study used the Taguchi orthogonal design to investigate the influence of laser power, scanning speed, gas flow, and SiC powder ratio on the micro-hardness and wear volume of the cladding layer. The results indicate that the SiC powder ratio was the major factor that had the main impact on the micro-hardness and wear volume of the cladding layer. The contribution of SiC powder ratio on the micro-hardness and wear volume are 92.08% and 79.39%, respectively. Through signal to noise ratio conversion and combining grey relational analysis, the multiple objectives optimization was attained. With the target of maximizing the micro-hardness and minimizing the wear volume simultaneously, grey relational analysis was applied to obtain the optimal processing parameters set and predict the corresponding grey relational grade. The error rate was 5.3% between the prediction and experimental validation. This study provides the guidance for optimizing multiple goals at the same time using grey relational analysis about the coating properties deposited by laser cladding in actual industrial applications. It provided theoretical basis for the processing parameters optimization with targeting the micro-hardness and wear resistance.


2018 ◽  
Vol 913 ◽  
pp. 390-395
Author(s):  
Yong Tian Wang ◽  
Jia Wei Mo ◽  
Lu Lu Tao

A large thick Fe based amorphous composite coating was deposited on the carbon steel substrate by laser cladding method. The phase composition and microstructure are characterized using X-ray diffraction and scanning electron microscope, respectively. The results demonstrate that the large thick laser cladding coating has a typical layered structure mainly consisting of amorphous and nanocrystal phases. The wear resistance and microhardness property are tested by the Vickers hardness tester and MLS-225 type wet sand rubber wheel abrasion tester. The results show that the large thick laser cladding coating has excellent wear resistance and hardness.


2020 ◽  
Vol 62 (11) ◽  
pp. 1078-1084
Author(s):  
Dang Kaifang ◽  
Jiang Zhiqiang

Abstract Laser cladding Ni-based WC reinforced composite coating was fabricated on the surface of Q235 steel using 6 KW fiber laser. The morphology, composition, microhardness and wear resistance of the composite coating at varied contents of WC particles were studied using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), microhardness tester and a wear tester. The results show that the dilution rate of the cladding layer decreases first and then increases with an increase of WC content. When the WC content is 20 wt.-%, the dilution rate is the smallest. In the process of fiber laser cladding Ni-based WC reinforced composite coating, WC particles partially dissolve and interact with other elements to form eutectics, which exist as lumpy shapes, strips and as spherical shapes. By increasing the WC content, the structure of the cladding layer appears to be refined. The main phases of the laser cladding layer are γ-Ni, M7C3, M23C6, CrB, WC and W2C. As the WC content increases, the hardness of the cladding layer increases. When the WC mass fraction reaches 40 wt.-%, the average hardness of the composite coating can be more than five times the substrate. When the mass fraction of WC is 20 wt.-%, the wear resistance of the cladding layer is best, which is more than three times that of Ni60A coating.


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