Evolution behavior of ex-situ NbC and properties of Fe-based laser clad coating

Cao, Ya-bin; Zhi, Shi-xin; Qi, Haibo; Zhang, Yang; Qin, Cha; Yang, Shaopu

doi:10.1016/j.optlastec.2019.105999

Cited by 15 publications

(7 citation statements)

References 26 publications

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“…A large surface tension gradient strengthens solution flow in the molten pool, causing the dendrites to break. The dendrite fragments act as the nuclei of new grains [ 27 , 28 , 29 ] to grow more fine grains.…”

Section: Resultsmentioning

confidence: 99%

Microstructures and Properties of NbC-Reinforced Ni-Based Coatings Synthesized In Situ by Ultrasonic Vibration-Assisted Laser Cladding

et al. 2023

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This paper aims to explore the mechanism of an ultrasonic applied field on the microstructures and properties of coatings, and clarify the evolution of the molten pool under different ultrasonic frequencies. The Taguchi experimental design method was adopted in this paper. NbC-reinforced Ni-based coatings were in situ synthesized by laser cladding to investigate the effects of ultrasonic vibration process parameters on the microstructure, pore area, microhardness, and wear resistance of the cladding layer. The results show that the pore area decreases first and then increases as ultrasonic power increases from 600 to 900 W and ultrasonic frequency from 23 to 40 kHz. On the contrary, the hardness and wear resistance increase at first and then decrease. The pore area is minimized at 800 W ultrasonic power and 32 kHz ultrasonic frequency, and the hardness is maximized at 600 W ultrasonic power and 40 kHz ultrasonic frequency. Meanwhile, the highest wear resistance can be obtained when ultrasonic power is 700 W and ultrasonic frequency is 32 kHz. Based on the phase structure analysis, the cladding layer mainly consists of FeNi3, NbC, B4C, and CrB2. Ultrasonic vibration will not change the phase composition of the layer. Combined with the varying G/R value and cooling rate, the reasons for the change in grain morphology in different areas were analyzed to reveal the evolution mechanism of the molten pool under the influence of ultrasound.

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Section: Resultsmentioning

confidence: 99%

Microstructures and Properties of NbC-Reinforced Ni-Based Coatings Synthesized In Situ by Ultrasonic Vibration-Assisted Laser Cladding

et al. 2023

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“…In this work, Ni60 alloy powder was chosen to repair the worn tooth of 20CrMnTi super gear owing to their similar hardness and melting point. Moreover, Ni60 alloy powder has excellent self-fluxing, high tenacity, good resistance, and good antioxidant activity [20,21]. The shape of Ni60 powder with a size of 100-270 mesh is nearly a sphere, as shown in Figure 1a.…”

Section: Materials and Experimental Set-upmentioning

confidence: 99%

Repair of Gear by Laser Cladding Ni60 Alloy Powder: Process, Microstructure and Mechanical Performance

Guan

Yú

et al. 2022

Applied Sciences

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As the main mechanical transmission parts, the gears are usually exposed to wear, corrosion, and fatigue; their failure in a poor working environment may cause a huge economic loss and waste of resources. Laser cladding (LC) has been proven to quickly repair parts at good metallurgical bonding performance and has flexible scanning strategies and a wide material selection. Therefore, LC technology can be considered an ideal approach to repairing damaged gear. However, the repair of damaged teeth by LC has not been systematically reported. In this paper, a series of progressive works have been carried out to systematically investigate the repair process of broken gears by LC. Firstly, process parameters, overlapping ratio, and Z-increment for Ni60 powder on 20CrMnTi were optimized. Secondly, the effects of deposition strategies on morphologies of single-layer and multi-layer multi-tracks were carefully analyzed. Then, the gear repair was successfully realized based on obtained optimized parameters. Finally, the phase composition, microstructure, hardness, and wear properties of the repaired gear tooth were analyzed by XRD, SEM, microhardness tester, and friction and wear tester. The results show that the remanufactured tooth can recover its appearance before breakage. The repaired zone is mainly composed of γ-Ni, Cr7C3, Cr23C6, and CrB phases. The micro-hardness and wear volume loss of the repaired zone is 60.63 ± 1.23HRC and 1674.983 μm2, which are consistent with those of the other teeth. This study is expected to expand the application of LC technology and provide guidance to engineers in the repair of damaged parts.

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“…This was because increased laser power had prolonged the span of the molten pool, increased thermal gradient, and enhanced heat convection. Part of Fe elements and Ti elements left by the decomposition of TiC was concentrated in the grain boundaries, and this grain boundary structure with relatively weak mechanical properties will further reduce the inter-grain bonding strength and increase the wear rate [18].…”

Section: Microstructure and Element Distributionmentioning

confidence: 99%

Microstructure Control and Friction Behavior Prediction of Laser Cladding Ni35A+TiC Composite Coatings

et al. 2020

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The premise of surface strengthening and repair of high valued components is to identify the relationship between coating formulation, structure, and properties. Based on the full factorial design, the effects of process parameters (laser power, scanning speed, gas-powder flow rate, and weight fraction of TiC) on the phase composition, microstructure, and element distribution of Ni35A/TiC cladding layer were investigated, followed by the cause identification of wear behavior. Through ANOVA, the correlation was established with good prediction accuracy (R2 = 0.9719). The most important factors affecting the wear rate of the cladding layer were recognized as laser power and particle ratio with a p-value < 0.001. The cladding layer was mainly comprised of Ni3Fe and TiC0.957. The excessive laser power would enhance the process of convection-diffusion of the melt pool, increase dilution, and improve wear volume. High laser power facilitates renucleation and growth of the hard phase, especially the complete growth of secondary axis dendrite for the top region. Increased TiC significantly changes the microstructure of the hard phase into a non-direction preferable structure, which prevents stress concentration at tips and further improves the mechanical properties. The research results are a valuable support for the manipulation of microstructure and prediction of wear behavior of composite cladding layer.

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Evolution behavior of ex-situ NbC and properties of Fe-based laser clad coating

Cited by 15 publications

References 26 publications

Microstructures and Properties of NbC-Reinforced Ni-Based Coatings Synthesized In Situ by Ultrasonic Vibration-Assisted Laser Cladding

Microstructures and Properties of NbC-Reinforced Ni-Based Coatings Synthesized In Situ by Ultrasonic Vibration-Assisted Laser Cladding

Repair of Gear by Laser Cladding Ni60 Alloy Powder: Process, Microstructure and Mechanical Performance

Microstructure Control and Friction Behavior Prediction of Laser Cladding Ni35A+TiC Composite Coatings

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