scholarly journals MICROSTRUCTURE EVOLUTION OF IN SITU COMPOSITE COATINGS FABRICATED BY LASER CLADDING WITH DIFFERENT POWERS

2021 ◽  
Vol 55 (3) ◽  
Author(s):  
Youfeng Zhang ◽  
Guangyu Han ◽  
Shasha He ◽  
Wanwan Yang
Keyword(s):  
Matrix Composite ◽  
Laser Cladding ◽  
Microstructure Evolution ◽  
Laser Power ◽  
Composite Coatings ◽  
Wear Properties ◽  
Fine Microstructure ◽  
Titanium Alloy Substrate ◽  
Friction And Wear Properties

In situ reaction-synthesized TiB-reinforced titanium-matrix composite coatings were fabricated using the rapid, non-equilibrium synthesis technique of laser cladding. The Ti and B mixture was the original powders, while the Ti-matrix composite coatings enhanced with TiB were treated on a Ti-6Al-4V surface with different laser scan powers of 2.5 kW, 3.0 kW and 3.5 kW. The phase composition, microstructure evaluation, and microhardness of the cladding coatings were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and microhardness. The composite coatings mainly consist of black fishbone-shaped -Ti dendrites and white needle-like TiB phases. The microstructure evolution from the top to the bottom of the coatings was investigated. The TiB reinforcement dispersed homogeneously in the composite coatings and a fine microstructure was obtained in a sample fabricated with a laser power of 3.0 kW. The microhardness of the cladding coatings fabricated by different powders was over 2-fold greater than that of the Ti-6Al-4V titanium alloy substrate and achieved a maximum average of 792.2 HV with the laser power of 3.0 kW. The microstructures and properties of the coatings were changed by adjusting of the laser cladding power. The effects of the laser scan power on the microstructure, hardness and friction and wear properties of the laser cladding coatings were investigated and discussed.

Microstructure of In Situ TiB Reinforced Titanium Matrix Composite Coatings by Laser Cladding with Different Pre-Placed Powder Thickness

2011 ◽  
Vol 239-242 ◽  
pp. 899-902
Author(s):  
You Feng Zhang ◽  
Jun Li
Keyword(s):  
Composite Coating ◽  
Matrix Composite ◽  
Laser Cladding ◽  
Powder Mixture ◽  
Composite Coatings ◽  
Matrix Composites ◽  
Titanium Matrix ◽  
Titanium Matrix Composite ◽  
Titanium Matrix Composites

In situ reaction synthesized TiB reinforced titanium matrix composites were fabricated using rapid non-equilibrium synthesis techniques of laser cladding. Titanium matrix composite were laser cladding treated on Ti-6Al-4V using Ti and B powder mixture, and the designed weight fractions of B were 10 wt.% in the starting powder mixture. The composite coating mainly consists of α-Ti and TiB. The reinforcement TiB is dispersed homogeneously in the composite coating with pre-placed powder thickness of 0.5mm. The influence of pre-placed powder thickness on microstructure of laser cladding coatings was discussed.

Microstructures and Properties of Ti Matrix Composite Coatings with Ex/In Situ TiC Reinforced

2012 ◽  
Vol 522 ◽  
pp. 183-186
Author(s):  
Qing Yu ◽  
Yao Ning Sun ◽  
Wen Lei Sun ◽  
Xu Dong Zhang
Keyword(s):  
Matrix Composite ◽  
Laser Cladding ◽  
Deleterious Effect ◽  
Composite Coatings ◽  
Pure Titanium ◽  
Micro Hardness ◽  
Maximum Value ◽  
Coarse Microstructure ◽  
Ti Powder

Using laser cladding technique, TiC reinforced Ti matrix composite coatings were fabricated by preplacing TiC, (Ti+C), (Ti+TiC) powders respectively on the TA2 pure titanium surface.By means of XRD, SEM and Hv-Test, microstructures and microhardness were investigated. The results show that phases of the coatings are all composed of TiC and α-Ti. Delamination phenomenon appears when laser clad pure TiC coating, which has deleterious effect on properties. TiC phase is in-situ synthesized during laser clad (Ti+C) coating, but microstructure is coarse. Microstructure of (Ti+TiC) coating is the most uniform and dense of the three coatings. The microhardness sequence of the three coatings is (Ti+TiC)>TiC>(Ti+C), and the maximum value is Hv1246, Hv1213 and Hv1135 respectively. The main reason leads to the highest micro-hardness of (Ti+TiC) coating is the Ti powder is beneficial to laser cladding and large amount of TiC reinforcement formed which is compact and uniform.

High Power Diode Laser Cladding of Wear Resistant Metal Matrix Composite Coatings

2013 ◽  
Vol 199 ◽  
pp. 587-592 ◽  
Author(s):  
Damian Michał Janicki
Keyword(s):  
Diode Laser ◽  
Laser Cladding ◽  
High Power ◽  
Heat Input ◽  
Laser Power ◽  
Composite Coatings ◽  
Power Level ◽  
Erosive Wear ◽  
Homogeneous Distribution ◽  
Wear Properties

The paper describes the application of high power direct diode laser (HPDDL), with a rectangular laser beam spot of size 1.8x6.8 mm, for the cladding of Ni-based alloy (NiSiB)+WC composite coatings. The laser cladding process was carried out with a direct injection of cladding powder into the melt pool. The influence of parameters, such as laser power beam (heat input) and WC particles size in the cladding powder on the coatings microstructure and wear properties was investigated. The microstructure and morphology of the coatings were assessed by optical and scanning electron microscopy. Wear properties of the coatings were investigated using abrasive and erosive wear tests. The results showed that a proper selection of laser cladding parameters provides non-porous coatings with excellent metallurgical bonding and a homogeneous distribution of WC particles. The dissolution of WC particles increases with the size of WC particles decreasing in the cladding powder and increasing the laser power level (heat input). The coatings containing WC particles in size range of 100-200 µm provide the highestwear resistance under erosive and abrasiveconditions.

FABRICATION OF IN SITUFe-Ti-B COMPOSITE COATING BY LASER CLADDING

2013 ◽  
Vol 20 (03n04) ◽  
pp. 1350034 ◽  
Author(s):  
BAOSHUAI DU
Keyword(s):  
Laser Cladding ◽  
Room Temperature ◽  
Composite Coatings ◽  
Solidification Path ◽  
X Ray Diffraction ◽  
Wear Properties ◽  
X Ray ◽  
Mild Carbon Steel ◽  
Liquid Precipitation

Laser cladding was applied to deposit in situ Fe - Ti - B composite coatings on mild carbon steel with precursor of ferrotitanium, ferroboron and pure Fe alloy powders. The composite coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron probe microanalysis (EPMA). Wear resistance of the laser-cladded Fe - Ti - B coatings was evaluated under dry sliding condition at room temperature using block-on-ring wear tester. Results indicate that in situ reinforcements of TiB 2 and Fe 2 B can be synthesized in the Fe - Ti - B coatings. The amount of TiB 2 increases with the increase of content of ferrotitanium and ferroboron in the precursor. Reinforcements are formed through the liquid-precipitation route following the solidification path of the Fe - Ti - B system. Hardness and wear properties of the coatings improved significantly in comparison to the as-received substrate due to the presence of hard reinforcements.

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