scholarly journals Study on the Effect of Ni Addition on the Microstructure and Properties of NiTi Alloy Coating on AISI 316 L Prepared by Laser Cladding

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4373
Author(s):  
Yuqiang Feng ◽  
Zexu Du ◽  
Zhengfei Hu
Keyword(s):  
Laser Cladding ◽  
Niti Alloy ◽  
Second Phase ◽  
Content Increase ◽  
Strengthening Effect ◽  
Mixed Powder ◽  
Microstructure And Properties ◽  
Cladding Layer ◽  
Ni Addition ◽  
Aisi 316 L

This paper investigated 55 NiTi commercial alloy powder and 55 NiTi with 5% pure Ni mixed powder (55 NiTi + 5 Ni) coatings fabricated by laser cladding to study the effect of extra Ni addition on the microstructure and properties of the coating. The XRD and EDS results show that the major phases in the coatings were NiTi and Ni3Ti. Besides that, a second phase like Ni4Ti3, Fe2Ti, and NiTi2 was also detected, among which, NiTi2 was only found in 55 NiTi coating. The proportion of the phase composition in the coating was calculated via the software Image-Pro Plus. The hardness of the cladding layer reaches 770–830 HV, which was almost four times harder than the substrate, and the hardness of 55 NiTi + 5 Ni coating was around 8% higher than that of 55 NiTi coating. The wear resistance of the 55 NiTi + 5 Ni coating was also better; the wear mass loss decreased by about 13% and with a smaller friction coefficient compared with the 55 NiTi coating. These results are attributed to the solid solution strengthening effect caused by Ni addition and the second phase strengthening effect caused by the content increase of the Ni3Ti phase in the cladding layer.

Effect on Microstructure and Hardness of Plunger Piston of Fe-Based Composite Coating by Laser Cladding

2011 ◽  
Vol 189-193 ◽  
pp. 830-833
Author(s):  
Yong Tao Zhao ◽  
Wen Xue Li ◽  
Jun Wei Zhou
Keyword(s):  
Wear Resistance ◽  
Laser Cladding ◽  
Second Phase ◽  
Micro Hardness ◽  
Hardness Testing ◽  
Matrix Metal ◽  
Cladding Layer ◽  
Hard Particles ◽  
The Matrix ◽  
Metal Microstructure

The laser cladding of Fe power technology was used to repair worn plunger piston surface. The microstructure of cladding layer, binder course and the matrix were observed by OM and SEM. Besides, the micro-hardness of different zones was measured through micro-hardness testing. The results show that the matrix metal microstructure of plunger piston is made of ferrite and austenite. By laser cladding Fe-based power on base metal, the cladding layer grain is fine and uniform, grain growth has obvious direction and finally become dendrites oriented, the microstructure of cladding layer is both second-phase hard particles and Fe-based solutes. The combination between matrix and cladding layer is smooth, belong to metallurgy bonding. The hardness of cladding layer is higher than that of other parts in three parts, the max value of micro-hardness is about 1250HV, it can agree with wear resistance need of plunge piston surface.

Research of Microstructure and Hardness of Co55 and W Coating Made by Laser Cladding

2015 ◽  
Vol 1120-1121 ◽  
pp. 694-697
Author(s):  
Wei Zhang
Keyword(s):  
Laser Cladding ◽  
Alloy Powder ◽  
Tungsten Powder ◽  
Weight Percent ◽  
Secondary Carbide ◽  
Mixed Powder ◽  
Dendritic Crystal ◽  
Cladding Layer ◽  
Average Hardness ◽  
Cladding Material

The experiment of laser cladding on the surface of 20 steel was made. The mixed powder of cobalt-based alloy powder (Co55) and tungsten powder was used as cladding material. There were three kinds of weight percent of tungsten powder, 5%, 10% and 15%. The microstructure and hardness of three kinds of laser cladding layer were studied. The microstructure of cladding zone was greatly refined after adding tungsten powder to Co55 powder. When the proportion of tungsten powder was 5%, the cladding zone was made up of dendritic crystal. The average hardness of cladding zone was 590 HV0.2. When the proportion of tungsten powder rose to 10%, there was reticular secondary carbide precipitating along the grain boundary. The average hardness of cladding zone was 648 HV0.2. When the proportion of tungsten powder rose to 15%, much granular carbide would diffusely distribute in Ni-based solid solution. The average hardness of cladding zone was 831 HV0.2.

scholarly journals Microstructure and Corrosion Behavior of Ti-Nb Coatings on NiTi Substrate Fabricated by Laser Cladding

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 597
Author(s):  
Jie Hu ◽  
Yaojia Ren ◽  
Qianli Huang ◽  
Hao He ◽  
Luxin Liang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Laser Cladding ◽  
Laser Processing ◽  
Niti Alloy ◽  
Processing Parameters ◽  
Medical Applications ◽  
Strengthening Effect ◽  
Aggressive Environment ◽  
Metallurgical Bonding ◽  
Fine Microstructure

Ti-23Nb (at.%) coatings on an NiTi alloy with metallurgical bonding were prepared by laser cladding (LC) technology using Ti-Nb mixture powders. The effects of laser processing parameters on the microstructure and mechanical properties of the coatings were systematically investigated and the corrosion resistance of the coatings was assessed. The coatings were composed of TiNb, (Ti, Nb)2Ni, and β-Nb phases. The coatings increased the hardness of the NiTi alloy by a combined strengthening effect of the eutectics and fine microstructure. The corrosion resistance of the coated part was improved. The coatings with great corrosion resistance could keep the coated parts inert in an aggressive environment, and effectively restrain the release of toxic Ni ions, which means that the Ti-Nb alloy coatings are likely to be used as a biomaterial for medical applications.

Microstructure and Properties of Ti2SC-Ti2Ni Composite Structural Phase Self-Lubricating Laser Cladding Layer on TC4 Surface

2020 ◽  
Vol 40 (11) ◽  
pp. 1114001
Author(s):  
张天刚 Zhang Tiangang ◽  
张倩 Zhang Qian ◽  
庄怀风 Zhuang Huaifeng ◽  
薛鹏 Xue Peng ◽  
姚波 Yao Bo ◽  
...  
Keyword(s):  
Laser Cladding ◽  
Structural Phase ◽  
Microstructure And Properties ◽  
Cladding Layer

Effect of Chromium Nitride on Microstructure and Properties of Fe-Based Coating by Laser Cladding

2010 ◽  
Vol 154-155 ◽  
pp. 1435-1438 ◽  
Author(s):  
Gui Hua Li ◽  
Yong Zou ◽  
Zeng Da Zou ◽  
Xiao Nan Li
Keyword(s):  
Laser Cladding ◽  
Austenite Phase ◽  
Experimental Results ◽  
Chromium Nitride ◽  
Microstructure And Properties ◽  
Cladding Layer ◽  
Solution Strengthening

In this paper, the Fe-based cladding layer was prepared on 42CrMo substrate by laser cladding mixture containing chromium nitride. The effects of chromium nitride on microstructure and property of cladding layer were studied. The experimental results indicate the chromium nitride is unstable during the process of laser cladding. It is very difficult to obtain chromium nitride in the laser cladding layer. However, the addition of chromium nitride in cladding powders could promote the formation of austenite phase, and increase the microhardness of cladding layer. The reason about increasing the microhardness of cladding layer is the formation of little carbide and solution strengthening of nitrogen, not the strengthening from chromium nitride.

scholarly journals Effect of Ni Addition on the Corrosion Resistance of NiTi Alloy Coatings on AISI 316L Substrate Prepared by Laser Cladding

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1139 ◽  
Author(s):  
Yuqiang Feng ◽  
Zexu Du ◽  
Zhengfei Hu
Keyword(s):  
Corrosion Resistance ◽  
Laser Cladding ◽  
Electrochemical Impedance ◽  
Niti Alloy ◽  
Steel Substrate ◽  
Energy Dispersive Spectrometer ◽  
Corrosion Current ◽  
Open Circuit ◽  
Pitting Potential ◽  
Ni Addition

In this paper, an equiatomic NiTi (55NiTi) alloy powder was mixed with pure Ni powder to prepare laser cladding coatings on a 316L stainless steel substrate to study the effect of Ni addition on the microstructure and corrosion resistance of the coatings. The microstructure and phase composition of the coatings were analyzed using a scanning electron microscope (SEM) with configured energy-dispersive spectrometer (EDS) and X-ray diffractometer (XRD). OCP (open-circuit potential), PD (potentiodynamic polarization) and EIS (electrochemical impedance spectroscopy) experiments were conducted by a Gamry electrochemical workstation, and corresponding eroded morphologies were observed to evaluate the coating’s anti-corrosion performance. The addition of Ni led to fine and uniform dendrites and dense microstructure under the metallurgical microscope, which were beneficial for the formation of the passive film mainly consisting of titanium dioxide (TiO2). The results show that the pitting potential of the 55NiTi + 5Ni coating was 0.11 V nobler than that of the 55NiTi coating, and the corrosion current density was less than half that of the 55NiTi coating. The corrosion initiated preferentially at the interfaces of dendrites and inter-dendritic areas, then spread first to dendrites rather than in the inter-dendritic areas.

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