Research on Microstructure and Hardness of Laser Cladding Using the Mixed Powder of Nano-TiC and Ni-Based Alloy

2020 ◽  
Vol 976 ◽  
pp. 9-14 ◽  
Author(s):  
Wei Zhang ◽  
Qiu Hong Feng ◽  
Wei Zhong Zhang
Keyword(s):  
Solid Solution ◽  
Wear Resistance ◽  
Composite Coating ◽  
Laser Cladding ◽  
High Speed ◽  
Scanning Speed ◽  
Mixed Powder ◽  
Reinforced Composite ◽  
Average Hardness ◽  
Cladding Material

Aiming at the problem of poor high-temperature wear-resistance of rope clamp used in super-high speed elevators, the experiments of laser cladding to prepare carbide reinforced composite coating were made. nanoTiC powder, Ni-based alloy powder were used as cladding material. The microstructure and hardness of composite coating were tested by relevant equipments. The research results show that the composite coating is made up of TiC, Cr3C2, Fe3C and Fe-Ni-Cr-C HYPERLINK "javascript:void (0);" solid solution. When the content of TiC is 10%, 30%, the morphology of TiC is presented as dendrite-like and the morphology of HYPERLINK "javascript:void (0);" solid solution is presented as cellular-like. When the content of TiC is 50%, the morphology of TiC is presented as block-like, lath-like. There are some microcracks on grain boundaries. At the content of 30%, laser power 1.5KW, scanning speed 600mm/min, the laser cladding has no crack and hole. The average hardness of composite coating is 701HV0.2. Using this technology to the surface strengthening of elevator parts, the wear resistance and service life can be greatly improved.

scholarly journals Microstructures and Wear Resistance of FeCoCrNi-Mo High Entropy Alloy/Diamond Composite Coatings by High Speed Laser Cladding

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 300 ◽  
Author(s):  
Haijiang Wang ◽  
Wei Zhang ◽  
Yingbo Peng ◽  
Mingyang Zhang ◽  
Shuyu Liu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Composite Coating ◽  
Laser Cladding ◽  
High Speed ◽  
Composite Coatings ◽  
Scanning Speed ◽  
High Entropy Alloy ◽  
Dilution Ratio ◽  
High Entropy ◽  
High Scanning Speed

FeCoCrNi-Mo high entropy alloy/diamond composite coatings were successfully prepared by high speed laser cladding. A high scanning speed was adopted (>30 mm/s), and the effects of laser power, scanning speed, and diamond content on the microstructure and wear resistance of the composite coating were studied. The processing parameters of laser cladding had significant influence on the dilution ratio, graphitization of diamond, and wear resistance of the composite coatings. When the laser cladding parameters were 3000 W of laser power and the high scanning speed of 50 mm/s, the composite coating exhibited a uniform microstructure, the lowest dilution ratio, and the best wear resistance. The wear resistance of the composite coating was enhanced with the addition of diamond, but microcracks also increased. When the amount of diamond was 15 wt.%, the best combination of microstructures and wear resistance was obtained.

Experimental Study of Nano-Al2O3 Particles Reinforced Fe-Based Composite Coating Made by Laser Cladding

2015 ◽  
Vol 1120-1121 ◽  
pp. 698-701
Author(s):  
Wei Zhang
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Experimental Study ◽  
Composite Coating ◽  
Laser Cladding ◽  
Cladding Layer ◽  
Average Hardness ◽  
Crystal Grains ◽  
Cladding Material ◽  
Three Phases

The experiment of laser cladding on the surface of Cr12 mold steel was made. Ni-coated nano-Al2O3 particles powder was used as cladding material. The microstructure and hardness of laser cladding layer were tested. The research showed that the compact cladding layer without crack, gas hole and other defects could be made by laser cladding. The cladding layer was made up of three phases, Fe-Ni solid solution, Fe-Cr solid solution and nano-Al2O3 particle. nano-Al2O3 particles enhanced the inhomogeneous nucleation of Fe-based alloy, refined the crystal grains and strengthened the mechanical properties of cladding layer. The average hardness of cladding zone was 900 HV0.2 which was 2.2 times higher than that of substrate.

Microstructure evolution and properties of a laser cladded Ni-Based WC reinforced composite coating

2020 ◽  
Vol 62 (11) ◽  
pp. 1078-1084
Author(s):  
Dang Kaifang ◽  
Jiang Zhiqiang
Keyword(s):  
Wear Resistance ◽  
Fiber Laser ◽  
Dilution Rate ◽  
Composite Coating ◽  
Laser Cladding ◽  
Mass Fraction ◽  
X Ray Diffraction ◽  
Cladding Layer ◽  
Reinforced Composite ◽  
Average Hardness

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.

SURFACE PROPERTIES OF THE IN SITU FORMED CERAMICS REINFORCED COMPOSITE COATINGS ON TI-3AL-2V ALLOYS

2012 ◽  
Vol 19 (02) ◽  
pp. 1250009 ◽  
Author(s):  
PENG LIU ◽  
WEI GUO ◽  
DAKUI HU ◽  
HUI LUO ◽  
YUANBIN ZHANG
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Composite Coating ◽  
Surface Properties ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Micro Hardness ◽  
Reinforced Composite

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.

Research of Microstructure and Hardness of Co55 and W Coating Made by Laser Cladding

2015 ◽  
Vol 1120-1121 ◽  
pp. 694-697
Author(s):  
Wei Zhang
Keyword(s):  
Laser Cladding ◽  
Alloy Powder ◽  
Tungsten Powder ◽  
Weight Percent ◽  
Secondary Carbide ◽  
Mixed Powder ◽  
Dendritic Crystal ◽  
Cladding Layer ◽  
Average Hardness ◽  
Cladding Material

The experiment of laser cladding on the surface of 20 steel was made. The mixed powder of cobalt-based alloy powder (Co55) and tungsten powder was used as cladding material. There were three kinds of weight percent of tungsten powder, 5%, 10% and 15%. The microstructure and hardness of three kinds of laser cladding layer were studied. The microstructure of cladding zone was greatly refined after adding tungsten powder to Co55 powder. When the proportion of tungsten powder was 5%, the cladding zone was made up of dendritic crystal. The average hardness of cladding zone was 590 HV0.2. When the proportion of tungsten powder rose to 10%, there was reticular secondary carbide precipitating along the grain boundary. The average hardness of cladding zone was 648 HV0.2. When the proportion of tungsten powder rose to 15%, much granular carbide would diffusely distribute in Ni-based solid solution. The average hardness of cladding zone was 831 HV0.2.

EFFECTS OF B4C AND CR3C2 ON MICROSTRUCTURE AND PROPERTIES OF LASER CLADDING CO-BASED ALLOY COATINGS

2020 ◽  
Vol 27 (12) ◽  
pp. 2050021
Author(s):  
YUFAN SUN ◽  
HANGUANG FU ◽  
SHUANGYE CHEN ◽  
XUELONG PING ◽  
SHUTING SUN ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Laser Cladding ◽  
Scanning Speed ◽  
Mold Surface ◽  
Test Results ◽  
Micro Hardness ◽  
Mixed Powder ◽  
Surface Strengthening ◽  
First Time ◽  
Poor Stability

Based on the background of automotive mold surface strengthening, the effects of three different enhancements on the microstructure evolution, micro-hardness and wear resistance of laser cladding cobalt-based coatings were studied. The three reinforcing materials were Co45 alloy powder, Co45/8% B4C mixed powder and Co45/8% B4C/5% Cr3C2 mixed powder. They were respectively used to conduct laser cladding on the surface of die steel with preset powder method, with laser power of 2000[Formula: see text]W and scanning speed of 4[Formula: see text]mm/s. According to the test results, the hardness and wear resistance of the cladding coating were the best when Co45/8% B4C powder was added. In addition, the study also found that B4C reacted with Cr3C2 during laser cladding to eventually generate Cr2B. The CrB2 generated for the first time during the reaction was transformed into the most stable Cr2B with an orthorhombic Fddd symmetry due to its poor stability. Therefore, the sample with Co45/8% B4C/5% Cr3C2 mixed powder was affected with a slight decrease in microhardness and wear resistance.

Study of Aging Treatment on the Coating with 3%Cu/Fe-Based Alloy Fabricated by Laser Cladding

2011 ◽  
Vol 391-392 ◽  
pp. 474-478
Author(s):  
Fang Zhou ◽  
Tao Zhu ◽  
Gao Li
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Wear Resistance ◽  
Composite Coating ◽  
Laser Cladding ◽  
Aging Treatment ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Preferred Direction

The composite coating with 3%Cu/ Fe-based alloy was fabricated on Q235A steel by laser cladding. The effect of aging treatment on the microstructure and properties of laser-cladded coating was investigated. The results show that there is α-Fe phase accompanied by the M7C3 with an orthorhombic crystal structure and M23C6 in the cladded coating. The preferred direction at (110) crystal plane exist in the α-Fe. The TEM observation shows that the high density dislocations exist in the martensite. When the cladded coatings are aged at 550 for 20 h and 30 h respectively, the ε-Cu particles precipitate dispersedly from the supersaturated α-Fe solid solution along the M7C3. The ε-Cu particles play the role of anchoring dislocation. The microhardness and the wear resistance of coatings are increased greatly after the aging treatment. The coating aged for 20 h at 550 presents the best wear resistance in the tested coatings. With aging time, the microhardness and the wear resistance of cladding coating are decreased.

MICROSTRUCTURES AND DRY SLIDING WEAR RESISTANCE OF THE LASER CERAMICS COMPOSITE COATING ON PURE Ti

2012 ◽  
Vol 19 (03) ◽  
pp. 1250017 ◽  
Author(s):  
PENG LIU ◽  
YUANBIN ZHANG ◽  
HUI LUO ◽  
YUSHUANG HUO
Keyword(s):  
Wear Resistance ◽  
Composite Coating ◽  
Laser Cladding ◽  
Dry Sliding Wear ◽  
X Ray Diffraction ◽  
Phase Constituent ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Modification Technique ◽  
Surface Performance

In this study, Al–Ti–Co was used to improve the surface performance of pure Ti . Laser cladding is an important surface modification technique, which can be used to improve the surface performance of pure Ti . Laser cladding of the Al–Ti–Co + TiB2 pre-placed powders on pure Ti can form ceramics reinforced the composite coating, which improved the wear resistance of the substrate. Characteristics of the composite coating were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness and wear tests. And the laser-cladded coating can also have major dilution from the substrate. Due to the action of the fine grain strengthening and the phase constituent, the wear resistance and microhardness of pure Ti surface were greatly improved.

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