Microstructure and Dry Sliding Wear Behavior of Laser Cladding (TiC+TiN)-NiCrWC Powder Composite Coating on DZ125 Superalloy

2012 ◽  
Vol 557-559 ◽  
pp. 1699-1703 ◽  
Author(s):  
Jun Zhou ◽  
Fa Qin Xie ◽  
Jing Fang Jia ◽  
Nai Ming Lin ◽  
Xiang Qing Wu

Ni-based TiN-TiC composite coating was fabricated on DZ125 superalloy surface by laser cladding. The phase constitution and microstructures were investigated by means of X-ray diffraction (XRD), optical microscope (OM) and scanning electron microscope (SEM). Microhardness measurements and wear experiments without lubrication were also accomplished. The experimental results showed that a pore- and crack-free coating with metallurgical bonding to the substrate was obtained. Solidification morphologies along the section of the coating varied from directional dendrite in the interface to random dendrite in the surface. The coating was mainly composed of γ-Ni, M23C6, TiN, TiC particles and a small amount of NiTi, respectively. The average microhardness of 705HK for the coating was 2.3 times higher than that of the substrate. Wear tests indicated that wear resistance of the coating was significantly improved compared with that of the substrate. The improvement in hardness and wear resistance was attributed to TiN and TiC phase and chromium carbide uniformly dispersed in the matrix of the Ni-based TiN-TiC composite coating.

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.


2010 ◽  
Vol 97-101 ◽  
pp. 1510-1513
Author(s):  
Jun Zhou ◽  
Fa Qin Xie ◽  
Yong Quan Li ◽  
Xiang Qing Wu

Co-based composite coatings reinforced by TiN particles were fabricated on Ni-based superalloy substrate by using a 5 kW CO2 laser. The microstructures and phases constitution of the composite coating were studied by means of optical microscope (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The microhardness and wear resistance of the coating were also examined. The results showed that the composite coating was mainly composed of γ-Co, TiN, TiC, (Cr, W)23C6 and Co3Ti. And different solidification morphologies, such as planar, cellular and dendrite, were obtained. Structural transformations were attributed to the temperature gradient and solidification rate in metal-melting region. It was found that the microhardness of the composite coating was enhanced prominently as compared to the substrate region, which should be due to the undissolved TiN and other new complicated phase. Friction and wear tests without lubrication showed that the addition of TiN particles into Co-based coating can improve its wear resistance significantly without evidently increasing the friction coefficient of coating.


2010 ◽  
Vol 139-141 ◽  
pp. 398-401
Author(s):  
You Feng Zhang ◽  
Jun Li

In situ reaction synthesized TiB reinforced titanium matrix composites were fabricated using rapid non-equilibrium synthesis techniques of laser cladding. TiB/Ti composite coating was treated on Ti-6Al-4V surface using Ti and B powder mixture by laser cladding. Microstructure and dry sliding wear behavior of the in situ synthesized TiB/Ti composite coatings were investigated by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), energy-dispersive spectroscopy (EDS), hardness tester and friction and wear tester. The composite coatings consist of Ti, TiB and intermetallic compounds. The TiB reinforcement dispersed homogeneously in the composite coatings. The wear tests show that the friction coefficient and wear weight loss ratio of the coatings is lower than that of the Ti-6Al-4V alloy. The composite coating was reinforced by the in situ synthesized TiB ceramic particles. Based on the SEM observation, effects of scan speed on hardness and wear resistance of the laser cladding coatings were investigated and discussed.


Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 296 ◽  
Author(s):  
Chao Sun ◽  
Nannan Lu ◽  
Huan Liu ◽  
Xiaojun Wang ◽  
Xiaoshi Hu ◽  
...  

In this study, the dry sliding wear behaviors of SiC particle reinforced AZ91D matrix composites fabricated by stirring casting method were systematically investigated. The SiC particles in as-cast composites exhibited typical necklace-type distribution, which caused the weak interface bonding between SiC particles and matrix in particle-segregated zones. During dry sliding at higher applied loads, SiC particles were easy to debond from the matrix, which accelerated the wear rates of the composites. While at the lower load of 10 N, the presence of SiC particles improved the wear resistance. Moreover, the necklace-type distribution became more evident with the decrease of particle sizes and the increase of SiC volume fractions. Larger particles had better interface bonding with the matrix, which could delay the transition of wear mechanism from oxidation to delamination. Therefore, composites reinforced by larger SiC particles exhibited higher wear resistance. Similarly, owing to more weak interfaces in the composites with high content of SiC particles, more severe delamination occurred and the wear resistance of the composites was impaired.


2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Tuba Yener ◽  
Azmi Erdogan ◽  
Mustafa Sabri Gök ◽  
Sakin Zeytin

Abstract The aim of this study was to investigate the effect of low-temperature aluminizing process on the microstructure and dry sliding wear properties of Mirrax steel. Low-temperature aluminizing process was applied on Mirrax steel at 600, 650, and 700 °C for 2, 4, and 6 h. The packs for the process were prepared using pure aluminum powder as aluminum deposition source. Ammonium chloride NH4Cl and Seydisehir Al2O3 powder were used as the activator and the inert filler, respectively. Scanning electron microscope (SEM)/energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis were applied for characterization of the coating surfaces. The through-thickness variation in the layer microstructure was determined and it was found to vary between 1 µm and 45 µm which increased with higher process temperature and time. After the deposition process, the coating layer hardness increased to 1000 HVN, whereas the hardness of the matrix was 250 HVN. The wear tests were performed using a ball-on-disc tribometer under 5 N load at room temperature and 500 °C on aluminized and untreated Mirrax steel. In both room temperature and high-temperature wear tests, it was determined that the aluminizing process increased the wear resistance of Mirrax steel. Increasing aluminizing time and temperature also increased the wear resistance. The uncoated and thin-coated samples generally exhibited wear in the form of plastic deformation and adhesion related ruptures. A high degree of tribological layer was observed on the wear trace on samples with high coating thickness, especially in high-temperature tests. Therefore, the volume losses in these samples were induced by fatigue crack formation and delamination.


2020 ◽  
pp. 2050046
Author(s):  
TIANWEI YANG ◽  
ZHAOHUI WANG ◽  
SHIHAI TAN ◽  
FU GUO

To increase the strength and wear resistance of material surfaces, various combinations of B4C and 80TiFe powder were mixed into a Fe60 self-fluxing alloy powder; the composite coatings reinforced by TiB2–TiC were successfully prepared on Q235 steel surfaces by laser cladding. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to study the microstructure and chemical and phase composition. Microhardness and wear testers were used to investigate the mechanical properties. The results show that the interfaces of composite coatings and substrate materials are excellent for metallurgical bonding. The block-like TiB2 particles and flower-like TiC particles are uniformly distributed in the cladding coating. When the mass fraction of the mixed powder is 30%, the average microhardness of the coating is approximately 1100 HV[Formula: see text], which is 50% higher than that without the mixed powder, and demonstrates the best wear with a performance twice as better as that of the substrate.


2014 ◽  
Vol 1061-1062 ◽  
pp. 538-541
Author(s):  
Zhi Hong Dong ◽  
Hong Yuan Fan

Cr/WC-Ni composite coating was prepared on Cr12MoV die steel by thermal spray technique, and then further treated using laser cladding technique. WC powders was coated Cr by D.C. magnetron sputtering method. The structure, composition, hardness, morphology were analyzed and measured by XRD and SEM and hardness tester. Tribological experiments were carried out on an abrasion machine. The results showed thatCr film prevented WC decomposition, and Cr/WC-Ni coating had the higher hardness values compared with WC-Ni coating. After the treatment with the laser cladding, the coating surface was uniform and compact and had no cracks, the boding between the matrix and coating surface had a good metallurgical bonding, and sub-surface showed a higher hardness.


2011 ◽  
Vol 675-677 ◽  
pp. 1299-1302 ◽  
Author(s):  
Xin Wei ◽  
Gui Qin Wang ◽  
Yong Feng Chang ◽  
Chao Liu

In this paper, WC-Ni60 alloy composite coating with different contents of WC particles was prepared on the 45steel substrate by high frequency induction cladding. The Composition and microstructure were characterized by X-ray diffraction (XRD) and electron probe X-ray microanalysis (EPMA), the abradability and hardness were tested by UMT-2 tribometer and HV-50A durometer, respectively. The results showed that the hardness and wear resistance of coating were enhanced with the increasing of WC content. WC-Ni60 coating obtained the best wear resistance with the content of 50% WC. The hardness of the coating got the highest when the content of WC was 60%, but wear resistance decreased. The WC-Ni60 coating was reinforced for various hard phases and the metallurgical bonding layer about 10μm was formed between coating and 45steel substrate.


2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Meiyan Li ◽  
Bin Han ◽  
Conghua Qi ◽  
Yong Wang ◽  
Lixin Song

The composite processing between laser cladding and low temperature (300°C) ion sulfurization was applied to prepare wear resistant and self-lubricating coating. The microstructure, morphology, phase composition, valence states, and wear resistance of the composite coating were investigated by scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), and friction and wear apparatus. The results indicate that the laser cladding Ni-based coatings and the maximum hardness of 46.5 HRC were obtained when the percent of pure W powder was 10%, composed of columnar dendrites crystals and ultrafine dendritic structure. After ion sulfurization at 300°C for 4 h, the loose and porous composite coating is formed with nanograins and the granularity of all grains is less than 100 nm, which consists ofγ-(Fe, Ni), M23C6carbides, FeS, FeS2, and WS2. Furthermore, the wear resistance of the composite coating is better than the laser cladding Ni55 + 10%W coating, and the friction coefficient and mass losses under the conditions of dry and oil lubrication are lower than those of laser cladding Ni55 + 10%W coating.


2018 ◽  
Vol 770 ◽  
pp. 106-115
Author(s):  
Jing Wen Qiu ◽  
Di Pan ◽  
Yong Liu ◽  
Ian Baker ◽  
Wei Dong Zhang

The wear behavior of powder metallurgical Ti-47Al-2Cr-0.2Mo alloy prepared by pre-alloyed powders was investigated using pin-on-disk wear tests in different environments, viz, argon, 4% hydrogen in nitrogen, air and oxygen. The disk material was sinter-hot isostatically pressed, yttria-stabilized zirconia. Lower wear rates were found for the TiAl pins in oxygen-free environments, indicating that oxygen play a key role in the wear rate. In contrast, the presence of molecular hydrogen and moisture have nearly no effect. A combination of X-ray diffraction and energy dispersive X-ray spectroscopy indicated that the abrasive particles present mainly consisted of the zirconia. In addition, zirconia particles were embedded in the worn tips of the TiAl pins and mixed into the tribolayers. The high stress and high contact temperature at the wear surface made the zirconia disk undergo a phase transformation during the dry sliding wear, accompanied by grain pullout, surface uplifting and microcracking. The hard tribolayer with embedded zirconia particles provides some protection against further wear of the TiAl pin. The highly localized, repetitive shear stress during the wear tests may bring about amorphous TiAl in the wear debris. The main wear mechanisms were abrasive wear of two-body and three-body, some delamination and plastic deformation.


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