scholarly journals Heat Treatment-Induced Microstructure and Property Evolution of Mg/Al Intermetallic Compound Coatings Prepared by Al Electrodeposition on Mg Alloy from Molten Salt Electrolytes

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1407
Author(s):  
Tianyu Yao ◽  
Kui Wang ◽  
Haiyan Yang ◽  
Haiyan Jiang ◽  
Jie Wei ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
Mg Alloy ◽  
X Ray Diffraction ◽  
Electron Backscattered Diffraction ◽  
Alloy Matrix ◽  
Comprehensive Properties ◽  
Compound Coatings ◽  
Compound Coating

A method of forming an Mg/Al intermetallic compound coating enriched with Mg17Al12 and Mg2Al3 was developed by heat treatment of electrodeposition Al coatings on Mg alloy at 350 °C. The composition of the Mg/Al intermetallic compounds could be tuned by changing the thickness of the Zn immersion layer. The morphology and composition of the Mg/Al intermetallic compound coatings were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and electron backscattered diffraction (EBSD). Nanomechanical properties were investigated via nano-hardness (nHV) and the elastic modulus (EIT), and the corrosion behavior was studied through hydrogen evolution and potentiodynamic (PD) polarization. The compact and uniform Al coating was electrodeposited on the Zn-immersed AZ91D substrate. After heat treatment, Mg2Al3 and Mg17Al12 phases formed, and as the thickness of the Zn layer increased from 0.2 to 1.8 μm, the ratio of Mg2Al3 and Mg17Al12 varied from 1:1 to 4:1. The nano-hardness increased to 2.4 ± 0.5 GPa and further improved to 3.5 ± 0.1 GPa. The Mg/Al intermetallic compound coating exhibited excellent corrosion resistance and had a prominent effect on the protection of the Mg alloy matrix. The control over the ratio of intermetallic compounds by varying the thickness of the Zn immersion layer can be an effective approach to achieve the optimal comprehensive performance. As the Zn immersion time was 4 min, the obtained intermetallic compounds had relatively excellent comprehensive properties.

Research on Properties of Amorphous Cr-C Alloy Coating in Crystallization Evolution

2012 ◽  
Vol 184-185 ◽  
pp. 1175-1180
Author(s):  
Guo Liang Li ◽  
Xiao Hua Jie ◽  
Bi Xue Yang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Intermetallic Compound ◽  
Adhesion Force ◽  
Alloy Coating ◽  
Treatment Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Proper Values ◽  
Peak Value

Amorphous Cr–C alloy coating was prepared by electrodepositing. The microhardness of the coating was tested after annealing from 100°C to 800°C and the crystallization evolution was studied by the analysis of X-ray diffraction (XRD) and differential scanning caborimetry (DSC). The results showed that the crystallization evolution of the coating began at 300°C and finished around 450°C, and intermetallic compound Cr7C3and Cr23C6appeared when heat treatment temperature reached around 600°C. The microhardness, corrosion resistance as well as the adhesion of the coating all increased first with the temperature and then dropped until it attained the proper values. The microhardness reached the maximum of 1610HV0.025at 600°C. While the corrosion resistance and the adhesion force attained the peak value at about 400°C.

Attrition Milling of CNT and Dispersion in Mg Alloy Matrix by Friction Stirring Process

2012 ◽  
Vol 590 ◽  
pp. 56-59 ◽  
Author(s):  
B.C. Yoo ◽  
Jai Won Byeon
Keyword(s):  
Solid State ◽  
Matrix Composite ◽  
Vickers Hardness ◽  
Metal Matrix ◽  
Rotation Speed ◽  
Mg Alloy ◽  
X Ray Diffraction ◽  
Alloy Matrix ◽  
X Ray ◽  
Attrition Milling

Effect of attrition milling and subsequent ultrasonification of CNT on dispersion in ethanol was investigated. An attempt was also made to disperse the CNT in Mg alloy matrix by solid state friction stirring process for fabrication of metal matrix composite. Attrition milling was performed at a rotation speed of 700rpm for various times up to 6 hour. After 2 hours of milling, amorphous trace was observed in X-ray diffraction pattern. Attrition milling and subsequent ultrasonification enhanced dispersion of CNT in ethanol. Mg alloy matrix composite dispersed with the CNT was successfully fabricated by friction stirring process. The CNT-dispersed composite was analyzed by optical microscopy and Vickers hardness.

Preparation of Ti2CuAl5 by Reactive Sintering

1988 ◽  
Vol 133 ◽  
Author(s):  
Arnulf J Maeland ◽  
Dave Narasimhan
Keyword(s):  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
Low Temperatures ◽  
Nickel Aluminides ◽  
Reactive Sintering ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Process ◽  
Microhardness And Microstructure

ABSTRACTThe exothermic formation of intermetallic compounds from the constituent powders through reactive sintering at relatively low temperatures is a promising new process being explored for the preparation of nickel aluminides. The process is useful for synthesis of other intermetallics as well.We describe here the preparation of Ti2CuAl5 using the technique of reactive sintering. This intermetallic compound has a L12 structure which is also the structure of the very interesting Ni3Al intermetallic. Characterization of the Ti2CuAl5 phase is done by x-ray diffraction, microhardness, and microstructure.

Interface Reaction between Tool Steel and Molten Al Alloy Containing High Mg Content

2017 ◽  
Vol 380 ◽  
pp. 115-119
Author(s):  
Young Ok Yoon ◽  
Nam Seok Kim ◽  
Bong Hwan Kim ◽  
Shae K. Kim
Keyword(s):  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
Tool Steel ◽  
Interface Reaction ◽  
Intermetallic Phases ◽  
Mg Alloy ◽  
Al Alloy ◽  
A380 Alloy ◽  
Mg Content

Interface reaction between SKD61 and three Al melts at 973 K was investigated in this study. In pure Al and A380 alloy, soldering occurred on the samples. Pure Al showed two separated soldering areas consisting of Fe-Al based intermetallic phases, mainly FeAl3. A380 alloy indicated the expanded soldering area consisting of Al3Fe and two AlFeSi based intermetallic phases. Al-10mass%Mg alloy showed the absence of soldering, but a formation of a few Fe-Al intermetallic phases. This would be attributed to weakened interaction between Fe and Al caused by Mg enrichment. Microstructures near soldering of pure Al and A380 also showed the precipitations considered as Al3Fe and AlFeSi intermetallic compounds, respectively. However, in Al-10mass%Mg alloy, there is only intermetallic compound including Mg, V and Ca without Al3Fe.

scholarly journals The Tribological Property and Microstructure of Ni-Ti Coating Prepared by Electrodeposition and Heat Treatment

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Chufeng Sun ◽  
Yanbin Wang ◽  
Qiong Su ◽  
Zhiguang Guo ◽  
Lei Shi
Keyword(s):  
Heat Treatment ◽  
Intermetallic Compounds ◽  
Tribological Property ◽  
Friction And Wear ◽  
Xrd Analysis ◽  
Nitrogen Atmosphere ◽  
Strengthening Effect ◽  
X Ray Diffraction ◽  
Plating Bath ◽  
Before And After

Ni-Ti coatings were fabricated by the electrodeposition in a Ni plating bath containing Ti power and heat treatment in nitrogen atmosphere. The surface morphology and microstructure of the Ni-Ti coating before and after heat treatment were analyzed by means of scanning electron microscopy and X-ray diffraction. The friction and wear behaviors of two different coatings were evaluated on a ball-on-disk UMT-2MT test rig. It was found that the phase structure of Ni-Ti coating heated in nitrogen was much different from that of the as-deposited Ni-Ti coating. Namely, the new intermetallic compounds, including Ni3Ti, NiTi, and NiTi2, and TiN were detected in the coating after heat treatment by the XRD analysis and contributed to greatly increasing the hardness and tribological property of the Ni-Ti coating, owing to the strengthening effect of the hard intermetallic compounds and TiN phase. At the same time, a small amount of intermetallic compounds and TiN was transferred from the composite coating to the rubbing surface of the counterpart steel ball during the sliding, which also contributed to decreasing the friction coefficient and increasing the wear resistance.

In-Situ Joining of Combustion Synthesized Ni3Al Intermetallic Compounds with AZ91D Mg Alloy

2007 ◽  
Vol 544-545 ◽  
pp. 383-386 ◽  
Author(s):  
Gue Serb Cho ◽  
Kang Rae Lee ◽  
Kyeong Hwan Choe ◽  
Kyong Whoan Lee ◽  
Ki Young Kim
Keyword(s):  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
Diffusion Layer ◽  
Nickel Aluminide ◽  
Coating Layer ◽  
Aluminide Coating ◽  
Mg Alloy ◽  
Ni3al Intermetallic Compound ◽  
Ni3al Intermetallic

We focused on the surface reinforcement of ligth weight casting alloys with Ni3Al intermetallic compounds by in-situ combustion reaction to improve the surface properties of nonferrous casting components. In the present work, by setting the mixture of elemental Ni and Al powders in a casting mold, the powder mixture reacted to form Ni3Al intermetallic compound by SHS reaction ignited by the heat of molten AZ91D Mg alloy and simultaneously bonded with the Mg casting alloy. The AZ91D Mg alloy bonded with the Ni3Al intermetallic compound was sectioned and observed by optical microscopy and scanning electron microscopy(SEM). The chemical composition of intermetallic compounds and diffusion layer formed around bonding interface were identified by energy dispersive spectroscopy(EDS), X-ray diffraction analysis(XRD) and electron probe micro analyzer(EPMA). The main intermetallic compound was Ni3Al phase and a little Ni2Al3 intermetallic compound was formed from the Ni and Al powder mixtures. Residual pores were observed in the synthesized intermetallic compound. The AZ91D Mg alloy and Ni3Al intermetallic compound were bonded very soundly by the interdiffusion of Mg, Ni and Al elements, but some cracks were observed around the bonded interface on the interdiffusion layer. The diffusion length formed between AZ91D Mg alloy and Ni3Al was different depending on the diffusivity of Ni and Al elements into the molten Mg alloy. Ni was more deeply diffused into the Mg alloy than Al. The diffusion layer was about 200m thickness and various phases were formed by the interdiffusion of Mg, Ni and Al. From this challenge we have successfully produced a coating layer based on nickel aluminide on ligth weight Mg alloy using molten metal heat without any additional process. On the basis of the results obtained, it is concluded that near-net shaped nickel aluminide coating layer can be formed using this unique process.

Microstructure characteristics of laser in situ synthesis high Niobium Ti-Al intermetallic compound coating under heat treatment

2017 ◽  
Vol 25 (6) ◽  
pp. 1477-1485
Author(s):  
刘洪喜 LIU Hong-xi ◽  
李正学 LI Zheng-xue ◽  
张晓伟 ZHANG Xiao-wei ◽  
郭新政 GUO Xin-zheng ◽  
王悦怡 WANG Yue-yi
Keyword(s):  
Heat Treatment ◽  
Intermetallic Compound ◽  
In Situ Synthesis ◽  
Microstructure Characteristics ◽  
Compound Coating

Assessing the Effect of Altering Secondary Phase in Friction Stir Processed AZ91 Mg Alloy by Solution Heat Treatment

2020 ◽  
Author(s):  
Hemendra Patle ◽  
Venkateswarlu Badisha ◽  
Yogeshwar Chakrapani Venkatesan ◽  
Siva Irullappasamy ◽  
Ratna Sunil B ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Solution Heat Treatment ◽  
Secondary Phase ◽  
Mg Alloy ◽  
Friction Stir

scholarly journals X-ray Determination of Compressive Residual Stresses in Spring Steel Generated by High-Speed Water Quenching

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1154
Author(s):  
Diego E. Lozano ◽  
George E. Totten ◽  
Yaneth Bedolla-Gil ◽  
Martha Guerrero-Mata ◽  
Marcel Carpio ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
High Speed ◽  
Spring Steel ◽  
X Ray Diffraction ◽  
Laboratory Equipment ◽  
X Ray ◽  
Water Chamber ◽  
Hardened Case ◽  
Compressive Residual Stresses

Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core microstructure. A special laboratory equipment was designed and built, which uses water as the quenching media in a high-speed water chamber. The severity of the cooling was characterized with embedded thermocouples to obtain the cooling curves at different depths from the surface. Samples were cooled for various times to produce different hardened case depths. The microstructure of specimens was observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to estimate the magnitude of residual stresses on the surface of the specimens. Compressive residual stresses at the surface and sub-surface of about −700 MPa were obtained.

scholarly journals Dual Electrochemical Treatments to Improve Properties of Ti6Al4V Alloy

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2479
Author(s):  
Stefano Rossi ◽  
Luciana Volgare ◽  
Carine Perrin-Pellegrino ◽  
Carine Chassigneux ◽  
Erick Dousset ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Combined Treatment ◽  
Amorphous Film ◽  
Amorphous Layer ◽  
Good Alternative ◽  
Surface Treatments ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Fluid Environment

Surface treatments are considered as a good alternative to increase biocompatibility and the lifetime of Ti-based alloys used for implants in the human body. The present research reports the comparison of bare and modified Ti6Al4V substrates on hydrophilicity and corrosion resistance properties in body fluid environment at 37 °C. Several surface treatments were conducted separately to obtain either a porous oxide layer using nanostructuration (N) in ethylene glycol containing fluoride solution, or bulk oxide thin films through heat treatment at 450 °C for 3 h (HT), or electrochemical oxidation at 1 V for 3 h (EO), as well as combined treatments (N-HT and N-EO). In-situ X-ray diffraction and ex-situ transmission electron microscopy have shown that heat treatment gave first rise to the formation of a 30 nm thick amorphous layer which crystallized in rutile around 620 °C. Electrochemical oxidations gave rise to a 10 nm thick amorphous film on the top of the surface (EO) or below the amorphous nanotube layer (N-EO). Dual treated samples presented similar results with a more stable behavior for N-EO. Finally, for both corrosion and hydrophilicity points of view, the new combined treatment to get a total amorphous N-EO sample seems to be the best and even better than the partially crystallized N-HT sample.

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