scholarly journals Study of Cracking Mechanism and Wear Resistance in Laser Cladding Coating of Ni-based Alloy

Author(s):  
Zhenglei Yu ◽  
Lunxiang Li ◽  
Deqiang Zhang ◽  
Guangfeng Shi ◽  
Guang Yang ◽  
...  

Abstract Ni-based coatings with the addition of a plastic phase- an austenitic stainless net were prepared using laser cladding technology, and the CeO2 was added in cladding layers. The cracking mechanism, microhardness, microstructure, phase composition, and wear properties were investigated. The relationship between thermal stress and the elastic and plastic fracture had been developed from the standpoint of fracture mechanics and thermal elastic fracture mechanics. The Fracture criterion of the nickel-based coating was obtained, and the study has shown that the crack sensitivity could be reduced by decreasing the thermal expansion coefficient Δα. Then a new method was proposed, in which the substrate was prefabricated the stainless steel net. It was found that the number of cracks reduced significantly with the addition of stainless steel net. When the stainless steel net with 14 mesh was added in Ni-based coatings, the average microhardness of nickel composite coating was 565 HV0.2, which was 2.6 times higher than that of the 45 steel substrate. Although the rare earth oxide 4 wt.% CeO2 and stainless steel net were added in the Ni-based coating reducing the microhardness (the average microhardness is 425 HV0.2), the wear resistance of it improved substantially. The wear volume of Ni-Based composite coating was 0.56×10-5mm3·N-1·m-1, which was 85.1% lower than that of 45 steel and 61.9% lower than that of Ni-based coating without CeO2 and stainless steel net. The experiment results have shown that the Nickel-based composite coating is equipped with low crack sensitivity and high abrasive resistance with austenitic stainless net and the rare earth oxide 4 wt.% CeO2.

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Zhenglei Yu ◽  
Lunxiang Li ◽  
Deqiang Zhang ◽  
Guangfeng Shi ◽  
Guang Yang ◽  
...  

AbstractNickel-based alloy coatings were widely used for the remanufacturing of dies and moulds by laser cladding, but the crack sensitivity would be increase due to the higher strength and hardness, which reduced the wear resistance of Ni-based alloys. In this paper, Ni-based coatings with the addition of a plastic phase (an austenitic stainless net) were prepared using laser cladding technology, and the CeO2 was added in cladding layers. The cracking mechanism, microhardness, microstructure, phase composition, and wear properties were investigated. The relationship between thermal stress and the elastic and plastic fracture had been developed from the standpoint of fracture mechanics and thermal elastic fracture mechanics. The fracture criterion of the nickel-based coating was obtained, and the study has shown that the crack sensitivity could be reduced by decreasing the thermal expansion coefficient Δα. Thus, a new method was proposed, which the stainless steel nets were prefabricated on the substrate. It was found that the number of cracks reduced significantly with the addition of stainless steel net. When the stainless steel net with 14 mesh was added in Ni-based coatings, the average microhardness of nickel composite coating was 565 HV0.2, which was 2.6 times higher than that of the 45 steel substrate. Although the rare earth oxide 4 wt.% CeO2 and stainless steel net were added in the Ni-based coating reducing the microhardness (the average microhardness is 425 HV0.2), the wear resistance of it improved substantially. The wear volume of Ni-based composite coating was 0.56×10−5 mm3·N−1·m−1, which was 85.1% lower than that of 45 steel. The experiment results have shown that the Nickel-based composite coating is equipped with low crack sensitivity and high abrasive resistance with austenitic stainless net and the rare earth oxide 4 wt.% CeO2. This research offers an efficient solution to produce components with low crack susceptibility and high wear-resistance coatings fabricated by laser cladding.


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.


Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 383 ◽  
Author(s):  
Da Shu ◽  
Xiangxiang Cui ◽  
Zhuguo Li ◽  
Jichao Sun ◽  
Jianbing Wang ◽  
...  

In this study, the addition of the rare earth oxide CeO2 was investigated to alter the microstructural properties of the nano-WC-reinforced Ni-based composite coatings. The reinforced composite was prepared on the 42CrMo steel surface using a semiconductor laser. The morphology and microstructure of coatings were analyzed using a scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Further, the digital microhardness tester and high-temperature friction and wear tester were used to observe the mechanical properties. The results indicated that the addition of CeO2 eliminated the cracks from the surface of the coatings and effectively reduced the number of pores. The phases were mainly observed as γ-Ni(Fe) in a solid solution, and some residual WC and W2C phases were observed. In addition, Fe3C, Cr23C6, M6C (M = W, Fe, and Ni), SiC and Cr7C3 composite carbides, Si2W and NiW tungsten compounds, and CeFe2- and CeNi2-containing Ce complex compounds were formed on the coating. The rare earth oxide CeO2 composite-modified coating mainly comprised dendrites, crystal cells, strips, and massive microstructures. The reinforced phases of the modified coating presented uniform dispersion distribution with the addition of 1% CeO2, and the structures were significantly refined. The maximum microhardness of the modified coating was approximately 1560 HV0.2, which was approximately 20% higher than that of the unmodified composite coating. The minimum wear loss of the modified coating was 6.1 mg and the minimum frictional coefficient was approximately 0.23, which were better than those of the unmodified coating. The wear mechanism of the nano-WC-reinforced Ni-based coating was primarily adhesive, whereas that of the CeO2 composite modified coating was mainly abrasive particle wear, which accompanied adhesive wear.


2013 ◽  
Vol 433-435 ◽  
pp. 2054-2057
Author(s):  
Peng Xu ◽  
Cheng Xin Lin ◽  
Xin Peng Yi ◽  
Chao Yu Zhou

AISI 304 stainless steel powder and Al2O3 powder was used to produce laser cladding composite coatings in order to improve the surface wear resistance of 45 steel. Microstructure of the composite coating was examined and analyzed by metallographic microscope. Microhardness and wear resistance of the composite under different scanning velocities were evaluated. The results show that the composite coating is composed of planar crystal, cellular crystal, dendritic crystal and fine equiaxed; the composite coatings under different technological parameters are made of the same phases, ferrite (α) and austenite (γ) phases. Microhardness of the composite is enhanced along with the increase of scanning velocity; effect of scanning velocity on wear loss of the composite coatings is not significant.


Wear ◽  
2010 ◽  
Vol 269 (11-12) ◽  
pp. 867-874 ◽  
Author(s):  
P. Tatarko ◽  
M. Kašiarová ◽  
J. Dusza ◽  
J. Morgiel ◽  
P. Šajgalík ◽  
...  

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.


2019 ◽  
Vol 39 (5) ◽  
pp. 0514001
Author(s):  
周建忠 Zhou Jianzhong ◽  
何文渊 He Wenyuan ◽  
徐家乐 Xu Jiale ◽  
谭文胜 Tan Wensheng ◽  
孟宪凯 Meng Xiankai ◽  
...  

2011 ◽  
Vol 38 (9) ◽  
pp. 0903007
Author(s):  
何祥明 He Xiangming ◽  
刘秀波 Liu Xiubo ◽  
杨茂盛 Yang Maosheng ◽  
石世宏 Shi Shihong ◽  
王明娣 Wang Mingdi ◽  
...  

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 636 ◽  
Author(s):  
Xu ◽  
Wang ◽  
Chen ◽  
Qiao ◽  
Zhang ◽  
...  

The effect of rare earth oxides on the microstructure and corrosion behavior of laser-cladding coating on 316L stainless steel was investigated using hardness measurements, a polarization curve, electrochemical impedance spectroscopy (EIS), a salt spray test, X-ray diffraction, optical microscopy, and scanning electron microscopy (SEM). The results showed that the modification of rare earth oxides on the laser-cladding layer caused minor changes to its composition but refined the grains, leading to an increase in hardness. Electrochemical and salt spray studies indicated that the corrosion resistance of the 316L stainless steel could be improved by laser cladding, especially when rare earth oxides (i.e., CeO2 and La2O3) were added as a modifier.


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