scholarly journals Effect of Vacuum Heat Treatment on Microstructures and Mechanical Properties of 7A52 Aluminum Alloy-Al2O3 Ceramic Brazed Joints

2021 ◽  
Vol 8 ◽  
Author(s):  
Deku Zhang ◽  
Xusheng Qian ◽  
Xiaopeng Li ◽  
Kehong Wang
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloy ◽  
Electroless Nickel ◽  
Amorphous Structure ◽  
Treatment Temperature ◽  
Vacuum Heat Treatment ◽  
Joint Shear Strength ◽  
Welding Temperature ◽  
7A52 Aluminum Alloy ◽  
Brazed Joints

This study investigated the interface morphology, microstructure composition and connection strength of 7A52 aluminum alloy-Al2O3 ceramic brazed joints under heat treatment conditions. Alumina ceramics were first treated with electroless nickel plating, followed by vacuum heat treatment at different temperatures. Then an Al-Si-Mg intermediate layer was placed between the treated alumina ceramic and 7A52 aluminum alloy for brazing under the conditions of welding temperature 590, holding time 1h, pressure 2 MPa. Results showed that when heat treatment was performed at 350°C and below, the nickel-plated metal had an amorphous structure, and when performed at 400°C, the nickel-plated layer had a crystalline structure and the brittle phase Ni3P was precipitated. When the heat treatment temperature was 350°C, the joint shear strength reached the maximum, which was 68.7 MPa.

The Effects of the Aging Temperature on the Microstructure and Corrosion Resistance of the Nickel-Phosphorus Composite Al2O3 Deposit

2012 ◽  
Vol 217-219 ◽  
pp. 101-104
Author(s):  
Li Ming Lian ◽  
Fang Fang Yan
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Aging Temperature ◽  
Corrosion Test ◽  
Steel Surface ◽  
Annealing Temperature ◽  
Electroless Nickel ◽  
Major Elements ◽  
Treatment Temperature ◽  
Chemical Plating

In this Paper, electroless nickel-phosphorus composite of Al2O3 deposit is prepared by chemical plating on 45 steel. Surface topography, microstructure and major elements are analyzed by SEM, EDS and XRD. The results show that the deposit is compact and the binding of the coating interface is very good. It is found that the microstructure of deposit is amorphous and after heat treatment is crystalline. Corrosion test showed that the coating's corrosion resistance is related to heat treatment temperature. It exhibits better corrosion resistance at annealing temperature of 250°C.

scholarly journals Electrical Resistivity and Tensile Strength Relationship in Heat-Treated All Aluminum Alloy Wire Conductors

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5738
Author(s):  
Nidal Alshwawreh ◽  
Baider Alhamarneh ◽  
Qutaiba Altwarah ◽  
Shamel Quandour ◽  
Shadi Barghout ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Electrical Resistivity ◽  
Aluminum Alloy ◽  
Mechanical Strength ◽  
High Performance ◽  
Treatment Time ◽  
Treatment Temperature ◽  
Exponential Relationship ◽  
And Control

Thermal processing of all aluminum alloy conductors (AAAC) is an important step that is performed to enhance the electrical and mechanical properties after the drawing process. In these 6xxx alloys, mechanical strength and electrical conductivity are normally two mutually exclusive properties. With the increased demand for high performance power conductors, it is important to understand and control microstructural evolution processes (e.g., recovery and the formation of nanoscale precipitates) in these alloys for better electrical and mechanical characteristics. In this study, heat treatment was performed on as-drawn 6201 AAAC wire conductors. The variations in tensile strength and electrical resistivity were quantitatively studied as a function of both the treatment temperature and holding time. Two wire diameters commonly used in the manufacturing of medium and high voltage power cables were used: 1.7 mm and 3.5 mm. From the obtained data, significant changes in the electrical resistivity and tensile strength were observed with increasing the treatment time. For both wire diameters, it was observed that the correlation between strength and resistivity can be described by a simple exponential relationship. This link could be useful in predicting mechanical strength by monitoring electrical resistivity variations during industrial heat treatment of AAAC wire conductors.

Characteristics of Electroless Nickel-Phosphorus-Potassium Titanate Whisker Composite Coating

2012 ◽  
Vol 472-475 ◽  
pp. 70-73
Author(s):  
Ya Xu Jin ◽  
Yu Ming Tian ◽  
Qiu Shu Li
Keyword(s):  
Heat Treatment ◽  
Composite Coating ◽  
Composite Coatings ◽  
Electroless Nickel ◽  
Medium Carbon Steel ◽  
Treatment Temperature ◽  
X Ray Diffraction ◽  
Potassium Titanate ◽  
Steel Substrates ◽  
Electroless Ni

Electroless nickel plating with potassium titanate whisker was co-deposited on medium carbon steel substrates. The microstructure of the composite coatings was investigated. The effect of aging temperature on the microstructure of the composite coatings was studied using X-ray diffraction. The results indicate that the composite coatings will turn into crystal state with increasing heat treatment temperature. Experimental results also show that a maximum hardness is achieved for the composite coating after heat treatment at 400°C for 1 hour. The corrosion resistance and tribological properties of the composite coatings are not inferior to those of electroless Ni-P coating.

Corrosion and Wear Behavior of Electroless Nickel Coatings

2020 ◽  
pp. 210-227
Author(s):  
Suman Kalyan Das ◽  
Supriyo Roy ◽  
Prasanta Sahoo
Keyword(s):  
Heat Treatment ◽  
Wear Behavior ◽  
Current Source ◽  
High Hardness ◽  
Electroless Nickel ◽  
Treatment Temperature ◽  
Corrosion And Wear ◽  
Uniform Coating ◽  
Nickel Coatings ◽  
Electroless Coatings

This chapter describes how corrosion is the degradation of a material due to a reaction with its environment. Wear is another deteriorating phenomenon which erodes the contacting surfaces of any mechanical component gradually. Although corrosion and wear are two different phenomenon they are often interdependent and in most practical situations take place simultaneously. Fortunately, several surface modification methods exist which can protect the surface of metal against corrosion and wear. Among them, electroless nickel coatings is a technology where a coating is applied without the use of external current source. The primary advantages of electroless coatings include uniform coating and ability to coat non-conductive materials. Electroless nickel coatings possess excellent properties such as high hardness, good wear resistance and corrosion resistance. The corrosion and wear behavior of these coatings mainly depend on bath ingredients, deposition conditions, heat treatment temperature, etc.

Morphology of Carbon Micro-Coils

2004 ◽  
Vol 449-452 ◽  
pp. 205-208
Author(s):  
M. Fujii ◽  
S. Motojima
Keyword(s):  
Heat Treatment ◽  
Lattice Structure ◽  
Diffraction Method ◽  
Chemical Vapor ◽  
Amorphous Structure ◽  
Treatment Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Higher Temperature

The double helical carbon micro-coils were obtained by chemical vapor deposition. As-grown carbon micro-coils with amorphous structure were heat-treated at various temperatures up to 3000°C . By heat treatment, the shape of the coils was not changed. The morphology of these coils was observed in detail using electron microscope. The lattice structure was analyzed by X-ray diffraction method. Heat treatment temperature dependence of the magnetoresistance and the measurement of Raman spectra suggest that the coils heattreated at higher temperature are more highly graphitized.

Microstructure Evolution during Solution Heat Treatment of Semisolid Cast 2024 Aluminum Alloy

2011 ◽  
Vol 339 ◽  
pp. 714-717 ◽  
Author(s):  
Siriwan Pannaray ◽  
Sirikul Wisutmethangoon ◽  
Thawatchai Plookphol ◽  
Jessada Wannasin
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloy ◽  
Solution Heat Treatment ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Grain Structure ◽  
Al Alloy ◽  
Solution Treatment Temperature ◽  
2024 Aluminum Alloy ◽  
Semi Solid

The aim of this study is to determine the appropriate solution treatment temperature and time of semi solid 2024 Al alloy. Solution heat treatment at 450°C and 480 °C for various times, from 4 hours to 16 hrs, were applied followed by artificial aging at 220 °C for 1 hr. Microstructure of the semi solid cast 2024 aluminum alloy mainly showed globular grain structure which consisted of matrix-α (Al) and grain boundary (GB) - eutectic phases (α+Al2CuMg/Al2Cu). Eutectic GB phases was found to completely dissolved after solution heat treatment at 480°C for 14 hrs while sample solution treated at 450°C for the same time showed the existence of remaining GB phases. Prolonging heat treatment after 14 hrs at both temperatures resulted in the formation of coarse black particles at the grain boundaries which were identified as Mg2Si phases. Therefore the suitable solution treatment of the alloy in this study was at 480°C for 14 hrs.

scholarly journals Microstructure and Mechanical Property of Al6Si2Cu Alloy Subjected to Double-Solution Heat Treatment

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 18
Author(s):  
Seongbin An ◽  
Minsuk Kim ◽  
Chaeeul Huh ◽  
Chungseok Kim
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aluminum Alloy ◽  
Intermetallic Phase ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Solution Temperature ◽  
Eutectic Si ◽  
Equilibrium Phases ◽  
Al Matrix

This study aims to develop the mechanical properties of the Al6Si2Cu aluminum alloy through the double-solution treatment. In addition to the Al matrix, large amounts of coarse eutectic Si, Al2Cu intermetallic, and Fe-rich phases were generated through thermo-calc simulation in agreement with the equilibrium phases. The eutectic Si phase is fragmented and spheroidized by the solution treatment as the heat treatment temperature and time increase. The Al2Cu intermetallic phase is dissolved into the Al matrix, resulting in an increase in both strength and elongation. The second-step solution temperature at 525 °C should be an optimum condition for enhancing the mechanical properties of the Al6Si2Cu aluminum alloy.

Effect of Heat Treatment on Microstructure and Corrosion Resistance of Ni-P/BN(h) Composite Coatings

2011 ◽  
Vol 239-242 ◽  
pp. 3362-3366
Author(s):  
Cheng Zhang Peng ◽  
Ling Ling Zhu ◽  
You Ming Chen
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Composite Coatings ◽  
Stable State ◽  
Amorphous Structure ◽  
Treatment Temperature ◽  
X Ray Diffraction ◽  
Pulse Electroplating ◽  
Heat Treated ◽  
Precipitated Phases

The Ni-P/ BN(h) composite coatings were prepared by pulse electroplating,and were heat treated at temperature of 200～400°C.The microstructure of the composite coatings was identified by X-ray diffraction,the corrosion behavior of the composite coatings in 3.5%NaCl and 10%H2SO4 solutions was investigated by the linear polarization measurements and scanning electron microscope (SEM).The results show that the as-deposited is an amorphous structure,the precipitated phases are Ni12P5 and Ni5P2 metastable state phases when heat treatment temperature is below 300°C,the precipitated phases is Ni3P stable state phase heat-treated at 400°C，the composite coating was crystallized in great degree.Both the as-deposited and heat treated composite coatings revealed best corrosion resistance in 3.5%NaCl and 10%H2SO4 solutions.

Diffusion Bonding between AZ91 Magnesium Alloy and 7075 Aluminum Alloy

2011 ◽  
Vol 308-310 ◽  
pp. 800-803 ◽  
Author(s):  
Fei Lin ◽  
Tie Peng Li ◽  
Qian Yu ◽  
Lu Lu Sun ◽  
Qing Sen Meng
Keyword(s):  
Shear Strength ◽  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
Holding Time ◽  
7075 Aluminum Alloy ◽  
Az91 Magnesium Alloy ◽  
Joint Shear Strength ◽  
Welding Temperature ◽  
Az91 Magnesium ◽  
Joint Shear

In the present investigation, AZ91 magnesium alloy was vacuum diffusion bonded to a 7075 aluminum alloy. The effects of the welding temperature and holding time on the joint shear strength are investigated with the help of electron microscopy, micro-hardness and electronic universal testing machine. It is shown that in certain extent, the welding temperature and holding time have great effect on the joint shear strength. The maximum of joint shear strength is obtained and the width of diffusion layer is 34.36μm with the bonding temperature being 470°C and the holding time reaching 60min.

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