Effects of Initial Powder Size on Microstructure and Corrosion Resistance of in situ (Ti-V)C Reinforced Fe-based Laser Cladding Layers

Author(s):  
Kai Chong ◽  
2014 ◽  
Vol 32 (11) ◽  
pp. 1095-1100 ◽  
Author(s):  
Hui ZHANG ◽  
Yong ZOU ◽  
Zengda ZOU ◽  
Chuanwei SHI

2011 ◽  
Vol 686 ◽  
pp. 646-653 ◽  
Author(s):  
Jing Liang ◽  
Sui Yuan Chen ◽  
Chang Sheng Liu ◽  
Feng Hua Liu

Two kinds of mixed powders:Ti-6Al-4V/B/C and Ti-6Al-4V/B4C which are pre-pasted or synchronized fed on Ti-6Al-4V substrates separately were scanned by a 500W pulsed YAG laser to induce in situ formation of titanium composite coatings contained TiBxand TiC ceramic reinforced phases. The influences of laser processing parameters including Pulse Frequency (PF), Pulse Width (PW), Laser Power (P) and Scanning Speed (V) together with the powder proportions on the microstructure and properties of the coatings were investigated. Microstructures, phase components of the coating were analyzed by OM, SEM, TEM and XRD respectively. Experimental results show that two and more kinds of ceramic reinforcements were in situ formatted in the matrix of Ti-6Al-4V. TiB and TiC ceramics were formed evenly with the morphology of needle, tiny dendrites and disperse particles in the prepasted single path specimens. For the powder feed laser cladding layers, the ceramic reinforcements were TiB (needlelike), TiB2(hexagonal prism or rodlike), a small amount of TiC (disperse particles) and non fully reacted B4C. The microhardness increased with the increase of the amount of B4C and B+C additions. When the added B and C contents are the same, the microhardness of the coating with B4C addition is higher than that of the coating with B+C addition. The average micro-hardness of a powder prepasted (with 20 wt.% B4C addition) multi-path laser cladding layer formed under the optimized processing parameters is up to 800HV, which is more than 2 times of that of the substrate (340Hv), and the wear weight loss of the layer decreased nearly 3 times that of the substrate.


2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Guangyu Han ◽  
Youfeng Zhang

Abstract Composite coatings of TiB were successfully obtained on the surface of a Ti–6Al–4V alloy by in situ laser cladding technology using Ti/B/Nd2O3 powders. The microstructure and corrosion resistance of the fabricated composite coatings were investigated because relevant studies have been thus far limited in this field. The results indicate that the cladding coating and the substrate combined well via metallurgy after laser cladding treatment, and no obvious cracks were observed in the cladding coatings. The coatings comprise only the TiB and the α-Ti phase. The addition of Nd2O3 promoted the formation of a uniform and refined microstructure of the cladding coatings, and a well-defined structure was obtained when the added Nd2O3 content was 2 wt%. The microhardness of the cladding coating obviously improved by 3 to 4 fold above that of the Ti–6Al–4V substrate. Moreover, the corrosion properties significantly improved by adding Nd2O3 into the coatings. Electrical impedance spectroscopy and polarization tests showed that the best corrosion resistance of the cladding coating was achieved with the addition of 2 wt% Nd2O3. All samples revealed obvious near-capacitive behavior after immersion in a corrosive medium.


Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 742 ◽  
Author(s):  
Yunpeng Liu ◽  
Hui Zhang ◽  
Guangchun Xiao ◽  
Wei Zhao ◽  
Hui Xu

By optimising the particle size of cladding alloy powders, in situ micron and submicron (Ti-V)C reinforced Fe-based laser cladding layers were prepared and the dry sliding friction properties were comparatively studied. Results showed that there were same phases of α-Fe, γ, TiC, and TiVC2 in the two cladding layers. The average grain size of the Fe-based matrix was 3.46 μm and 3.37 μm, the microhardness was 731 HV0.2 and 736 HV0.2, and the area ratio of carbides was 11.14% and 11.02%, respectively. The dry sliding wear resistance of the cladding layer reinforced by 1.95 μm carbides was 2.76 times higher than that of the 0.49 μm carbides. The failure mechanism of the cladding layer with the micron carbides was mainly caused by plastic deformation of the cladding layer matrix, whereas that of the submicron carbides involved both the plastic deformation of the cladding layer matrix and the abrasion that was caused by the peeled carbides.


2010 ◽  
Vol 150-151 ◽  
pp. 1429-1432
Author(s):  
Gui Hua Li ◽  
Yong Zou ◽  
Zeng Da Zou ◽  
Xu Wei Dong

The Fe-based composite coating reinforced by in situ synthesized multiphase ceramic particles has been successfully prepared by laser cladding preplaced powder on 42CrMo steel. The experimental results of X-ray diffraction and scanning electron micrograph indicate the coating is consisted by γ-Fe phase and Fe-Cr fine phase which possesses the better oxidation resistance and corrosion resistance. In-situ synthesized V(C,N), Cr2B3 and Cr3C2 particulates which are uniformly distributed in the composite coatings. The wear test showed that these reinforcement particulates improved significantly wear resistance of the coatings. The wear mass loss of the coating is about one tenth of the 42CrMo substrate. Laser cladding layers have better oxidation resistance. The oxide scale of the coatings is one eighth of the substrate through 750 constant temperature for 120h oxidation.


2008 ◽  
Author(s):  
Ruiquan Kang ◽  
Mingxing Ma ◽  
Wenjin Liu ◽  
Minlin Zhong ◽  
Yide Kan ◽  
...  

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