AMORPHOUS/NANOCRYSTALLIZATION OF TiN-TiB2 REINFORCED LASER CLAD COMPOSITES

2019 ◽  
Vol 26 (09) ◽  
pp. 1950057
Author(s):  
MOLIN SU ◽  
JIANING LI ◽  
XUEGANG WANG ◽  
ZHIYUAN LIU

Laser cladding (LC) of the Stellite6-BN-Cu-Y2O3 pre-placed powders on the Ti-6Al-4V alloy substrate formed the bulk TiN and needle-like Ti-B compounds reinforced composites, which improved the wear resistance of the substrate surface. The results showed that lots of the amorphous-nanocrystalline phases were produced in such composites; the proper content of Cu was used to refine microstructures, also a large number of the nanocrystals can be formed; the elements such as Co, Ni and Fe in Stellite6 favored the amorphous phase to be formed. The addition of Y2O3 improved the fluidity of the liquid metal, also retarding the growth of the dendrite, leading the fine microstructures to be formed, improving the property of the LC composites.

Author(s):  
Shingo Iwatani ◽  
Yasuhito Ogata ◽  
Keisuke Uenishi ◽  
Kojiro F. Kobayashi ◽  
Akihiko Tsuboi

In order to improve a wear resistance of aluminium alloy, we proposed a diode laser cladding on the surface of a A5052 aluminium alloy. Firstly, an applicability of diode laser to laser cladding was evaluated. In this result, application of diode laser made it possible to obtain stable beads in low heat input compared with CO2 laser. According to the increase in aluminium content in the obtained clad layer, the microstructure of the clad layer changed as γ (8∼20%) → γ + α (10∼30%) → Fe3Al (30%∼). At the interface between the clad layer and the aluminium alloy substrate, the reaction layer consisting of Fe2Al5 and FeAl3 formed. In the abrasion wear the obtained clad layers exhibited a higher wear resistance compared with the aluminium alloy.


Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 407 ◽  
Author(s):  
Yuxin Li ◽  
Pengfei Zhang ◽  
Peikang Bai ◽  
Keqiang Su ◽  
Hongwen Su

In this paper, TiBCN-ceramic-reinforced Ti-based coating was fabricated on a Ti6Al4V substrate surface by laser cladding. The correlations between the main processing parameters and the geometrical characteristics of single clad tracks were predicted by linear regression analysis. On this basis, the microstructure, microhardness, corrosion resistance, and wear resistance of the coating and the substrate were investigated. The results showed that the clad height, clad width, clad depth, and dilution rate depended mainly on the laser power, the powder feeding rate, and the scanning speed. TiBCN-ceramic-reinforced Ti-based coating was mainly composed of directional dendritic TiBCN phases, equiaxed TiN phases, needle-like Al3Ti phases, and Ti phases. The microhardness gradually increased from the bottom to the top of the coating. The highest microhardness of coating was 1025 HV, which was three times higher than that of the Ti6Al4V substrate (350 HV). Furthermore, the coating exhibited excellent corrosion resistance and wear resistance. The corrosion potential (Ecorr) reached −1.258 V, and the corrosion density (Icorr) was 4.035 × 10−5 A/cm2, which was one order lower than that of the Ti6Al4V substrate (1.172 × 10−4 A/cm2). The coating wear mass loss was 4.35 mg, which was about two-third of the wear mass loss of the Ti6Al4V substrate (6.71 mg).


2019 ◽  
Vol 49 (5) ◽  
pp. 361-364
Author(s):  
N. B. D’yakonova ◽  
D. L. D’yakonov ◽  
B. A. Kornienkov ◽  
V. P. Filippova

2012 ◽  
Vol 271-272 ◽  
pp. 3-7
Author(s):  
Long Wei ◽  
Zong De Liu ◽  
Xin Zhi Li ◽  
Ming Ming Yuan ◽  
Cheng Yuan Zhong

Cr3C2-NiCr has high quality of wear resistant properties and is widely used in abrasive environment. In this paper, Cr3C2-NiCr coating was prepared on 45 steel by laser cladding technology. Analysis and research of the coatings were achieved by SEM and XRD to determine the main component and the different region on coatings. The hardness and the element component were investigated by micro-hardness tester and EDS. Abrasion tests were performed to contrast the wear resistance of two materials. The results indicate that the hardness of the coatings is nearly 3 times as the substrate. The coatings are well combined with the substrate and the phase of Cr3C2 has a large proportion in the coatings. Abrasion tests show that the average of wear rate on substrate is 5.2 times as the coatings.


2008 ◽  
Vol 373-374 ◽  
pp. 304-307
Author(s):  
Sen Yang ◽  
Ming Run Wang ◽  
Tao Gong ◽  
Wen Jin Liu

In order to improve wear resistance of carbon steel, laser cladding experiments were carried out using a 3kW continuous wave CO2 laser. The diameter of the laser beam was 3-5mm, the scanning velocity was 3-10mm/s, and the laser output power was 1.0-1.3kW. The experimental results showed that MoSi2/SiCP composites coating could be in-situ synthesized from mixture powders of molybdenum, silicon and SiC by laser cladding. A good metallurgical bond between the coating and the substrate could be achieved. The microstructures of the coating were mainly composed of MoSi2, SiC and FeSiMo phases. The average microhardness of the coating was about HV0.21300, about 6.0 times larger than that of steel substrate.


2012 ◽  
Vol 19 (03) ◽  
pp. 1250017 ◽  
Author(s):  
PENG LIU ◽  
YUANBIN ZHANG ◽  
HUI LUO ◽  
YUSHUANG HUO

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.


2013 ◽  
Vol 20 (4) ◽  
pp. 307-310
Author(s):  
Li Wei

AbstractA hard SiC-B4C reinforced composite coating was fabricated by laser alloying of SiC-B4C+Al-Sn-Mo-Y2O3 mixed powders on a Ti-3Al-2V alloy. Al-Sn-Mo mixed powders were first used in the laser alloying technique to improve the wear resistance of titanium alloys. Proper selection of the laser alloying process parameters allows us to obtain a composite coating with a metallurgical combination with substrate. Under the action of Mo, fine particles with high microhardness were produced in the coating matrix and also hindered the formation of adhesion patches and deep plowing grooves during the sliding wear process, leading to the improvement of wear resistance of a titanium alloy substrate surface.


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.


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