scholarly journals Superplastic Forming and Reaction Diffusion Bonding Process of Hollow Structural Component for Mg-Gd-Y-Zn-Zr Rare Earth Magnesium Alloy

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 152
Author(s):  
Peng Peng ◽  
Shaosong Jiang ◽  
Zhonghuan Qin ◽  
Zhen Lu

This work fabricated a double hollow structural component of Mg-8.3Gd-2.9Y-0.8Zn-0.2Zr alloy by superplastic forming (SPF) and reaction-diffusion bonding (RDB). The superplastic characteristic and mechanical properties of Mg-8.3Gd-2.9Y-0.8Zn-0.2Zr alloy sheets at 250–450 °C were studied. Tensile tests showed that the maximum elongation of tensile specimens was about 1276.3% at 400 °C under a strain rate of 1 × 10−3 s−1. Besides, the effect of bonding temperature and interface roughness on microstructure and mechanical properties of the reaction diffusion-bonded joints with a Cu interlayer was investigated. With the increase of temperature, the diffusion coefficient of Cu increases, and the diffusion transition region becomes wider, leading to tightening bonding of the joint. However, the bonding quality of the joint will deteriorate due to grain size growth at higher temperatures. Shear tests showed that the highest strength of the joints was 152 MPa (joint efficiency = 98.7%), which was performed at 460 °C.

Author(s):  
Nader Nadermanesh ◽  
Abdolhamid Azizi ◽  
Sahebali Manafi

The diffusion bonding of 7075, 6061 and 5083 aluminium alloys to AZ31B magnesium was investigated using copper interlayer. An optical microscope along with scanning electron microscopes, equipped with an energy dispersive spectrometry/electron probe microanalysis, was utilized to characterize the microstructure of the joint. The mechanical properties of the joint were also assessed by micro-hardness and shear strength tests. The results indicate the high effect of temperature on the bonding results; so that, with a small change in temperature, severe changes were observed in the bonding results. A temperature range of 475°C–485°C and a minimum duration of 30 min with a low bonding pressure of 0.4 MPa were identified as advisable process conditions. The joint evaluation revealed the formation of CuAl2, Cu9Al4 and Al-Mg-Cu ternary phases on the aluminium-copper side, as well as Cu2Mg, CuMg2 and Al-Mg-Cu ternary phases on the magnesium-copper side in the reaction layer. When increasing the bonding temperature and duration, the amount of intermetallic compounds and, as a result, the mechanical properties of the joints changed. The highest shear strength and micro-hardness, related to the bonding performed at 480°C and holding time of 45 min, were 31.03 MPa and 167 HV, respectively.


Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 376
Author(s):  
Thomas Gietzelt ◽  
Mario Walter ◽  
Volker Toth ◽  
Florian Messerschmidt ◽  
Ralf Dahm

Sulfuric acid is a widely used raw material in the chemical industry. Its corrosive effect on materials varies considerably, depending on impurities, temperature and water content. This is an issue for micro process apparatuses with thin walls. Such devices are often joint by diffusion bonding what may alter materials properties due to high temperatures and long dwell times. In this paper, two high molybdenum alloys, namely Hastelloy B3 and BC-1, were investigated. Diffusion bonding tests were performed at different temperatures. Tensile tests were carried out for different material conditions, to determine the change in mechanical strength and elongation at fracture values. The fracture behavior of both alloys was ductile and the fracture surfaces showed dimple structure. For diffusion bonded samples, weak spots or rather non-bonded areas were found. These obviously caused the onset of material failure and thus, degradation of mechanical properties. Tensile samples, aged in 70% sulfuric acid at 100 °C for 1000 h showed local corrosion attacks at the grain boundaries at the circumferential surfaces and joining planes—for Hastelloy B3 more pronounced than for Hastelloy BC-1. Accordingly, a further decrease of stress and elongation at fracture values was observed. However, 0.2% yield strength used for dimensioning components are found to be reasonable. As conclusion, at least Hastelloy BC-1 reveals both good mechanical properties and an excellent corrosion resistance, regardless of the heat treatment. This is a significant advance compared to the results obtained from a previously research project on four different alloys.


2014 ◽  
Vol 59 (1) ◽  
pp. 127-131 ◽  
Author(s):  
J. Bogucka

Abstract The influence of bonding temperature on microstructure and mechanical properties of AA5251 alloy sheets have been analyzed in the paper. The alloy was deformed with the method of accumulative roll bonding (ARB) in various temperature conditions i.e. at ambient temperature up to 5th cycle (ε = 4.0) and using pre-heating of sheet packs at 200°C and 300°C up to 10 cycles (ε = 8.0). The deformed material was subjected to structural observations using TEM, measurements of crystallographic texture with the technique of X-ray diffraction and tensile tests. It was established that the temperature of roll-bonding had a significant effect on the structure evolution and the observed changes of mechanical properties. High refinement of microstructure and optimum mechanical properties were obtained for the material processed at lower temperatures, i.e. at ambient temperature and pre-heating at 200°C. Recovery structure processes occurring during deformation were observed in the alloy bonded with pre-heating at 300°C and therefore mechanical properties were lower than for the alloy bonded at lower temperatures.


2007 ◽  
Vol 551-552 ◽  
pp. 163-168
Author(s):  
Wen Bo Han ◽  
D.Z. Wu ◽  
Guo Feng Wang ◽  
M.J. Tong

The superplastic forming and diffusion bonding (SPF/DB) is applied in aviation and space flight field. The SPF/DB process with gas pressure control for dissimilar superalloy structure was studied. Diffusion bonding parameters, including bonding temperature T, pressure P, time t, affect the joining mechanism. When the bonded specimen with 50&m thick nickel foil interlayer was tensile at room temperature, shear fracture of the joints with nickel foil interlayer takes place at the GH4141 superalloy part. The SPF/DB of four-layer sheets structure was investigated. The optimum parameters for the SPF/DB process are: forming temperature T=1243K, forming pressure P=1MPa, forming time t=35min. The microstructure of the bonded samples was characterized. The microstructure shows an excellent bonding at the interfaces. The distribution of thickness after SPF/DB was investigated.


Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1158
Author(s):  
Yajie Du ◽  
Zhaoxi Li ◽  
Jiangtao Xiong ◽  
Yipeng Chen ◽  
Shiwei Li ◽  
...  

The superalloy FGH98 was successfully diffusion bonded (DB) with medium-entropy alloy (MEA) Al3Ti3(CrCoNi)94 using pure Ni as the interlayer at a temperature range of 1050–1170 °C for 1 h under 5 MPa. The microstructure and mechanical properties of joints were investigated. The diffusion bonding seam was composed of an interlayer zone (IZ) and two diffusion-affected zones (DAZ). The IZ and DAZ beside the FGH98 consisted of cubic Ni3(TiAl)-type γ′ phases due to the diffusion of Ti and Al atoms. Meanwhile, the DAZ adjacent to the MEA consisted of spherical γ′ phases. Both of the γ′ phases with different morphology kept the coherent relationship with the matrix. Moreover, increase of bonding temperature led to the morphology of interlayer γ′ phase to transform from sphere to cube. Due to the strengthening effect of a mass of γ′ phase distributed evenly in IZ and the DAZ beside the FGH98, the microhardness and Young’s modulus of these two zones were higher than that of DAZ near the MEA. The maximum shear strength of DB joint, 592 MPa, was achieved in the joint bonded by 1150 °C, which was the typical ductile fracture feature confirmed by the shear dimples.


Author(s):  
Thomas Gietzelt ◽  
Mario Walter ◽  
Volker Toth ◽  
Florian Messerschmidt ◽  
Ralf Dahm

Sulphuric acid is a widely used raw material in the chemical industry. Its corrosive effect on materials varies considerably, depending on impurities, temperature and water content. Accordingly, good corrosion resistance under all conditions is very difficult to achieve. This is especially an issue for micro process apparatus with very thin walls. Furthermore, such devices are often joint by diffusion bonding what may alter materials properties due to high temperatures and long dwell times. In fact, for each new material, the diffusion bonding parameters must be optimized and the impact on mechanical as well as corrosion properties must be investigated. In this paper, two high molybdenum alloys, namely Hastelloy B3 and BC-1, were evaluated. Diffusion bonding tests were performed using ten layers of sheet material in between round stock. Corrosion tests were performed in 70 % sulphuric acid at 100°C for 1000 h. Tensile tests on both alloys were carried out for different material conditions, to determine the change in mechanical strength and elongation at fracture values. In general, independent of the condition of the materials, the fracture behavior of both alloys was found to be ductile and the specimens show the typical dimple structure, in the case of diffusion bonded samples, interrupted by weak spots or rather non-bonded areas. These areas are obviously causing the onset of material failure and thus, a degradation of mechanical properties. Tensile samples, that were aged in 70% sulphuric acid at 100°C for 1000 hours showed local corrosion attacks at the grain boundaries at the circumferential surfaces and especially at the joining planes – for Hastelloy B3 much more pronounced than for Hastelloy BC-1. Accordingly, a further decrease of both, the stress- and elongation at fracture values is observed. However, the typical material parameters like 0.2 % yield strength used for dimensioning components are found to be sufficient high, even when operating the materials under such harsh conditions. When concluding the results, at least Hastelloy BC-1 reveals both sufficient good mechanical properties and an excellent corrosion resistance, regardless of the heat treatment, and could be considered for manufacturing micro-process engineering apparatuses operated in a sulphuric acid environment. This is a significant advance compared to the results obtained within a AiF project, previously carried out on four different materials to investigate the corrosion resistance in sulphuric acid.


2007 ◽  
Vol 551-552 ◽  
pp. 49-54 ◽  
Author(s):  
Zhi Qiang Li ◽  
X.H. Li

Superplastic forming and diffusion bonding (SPF/DB) processes have been growing mature and titanium SPF/DB components have found wide application in aerospace industry. With the development of industrial SPF/DB technology, the size of SPF/DB components become bigger and bigger, and the shapes of components become more complex. However, the component sizes are limited by equipments, dies and the size of sheet. SPF/DB combined with welding technologies could be one of the possible solutions to form larger and more integrated structures due to many advantages compared with conventional process. This paper studied the combination processing of SPF and other welding methods besides diffusion bonding, such as electron beam welding and laser beam welding, and explained the experiments performed in different processes, including SPF after welding plate and welding plate after SPF. The results show that the material exhibits both reasonable formability and excellent mechanical properties. Application samples such as covers were manufactured by the combination processing. Furthermore, prospects of the combining technology were discussed at the end of paper.


2014 ◽  
Vol 936 ◽  
pp. 1647-1652
Author(s):  
Yan Ling Zhang ◽  
Hong Liang Hou ◽  
Yao Qi Wang

Superplastic forming (SPF) is an important process for forming fine grained 1420 Al-Li alloy. However, the mechanical properties will be decreased after deforming at high temperature. How to obtain the optimize relationship of strength and ductility after SPF is one of the key problems for the process. In this paper, a set of artificial aging tests including single and two-step aging were carried out, which are the typical strengthening process for Al-Li alloy. Based on experimental results, strength and elongation were studied by means of tensile tests at room temperature, and the effect of aging processes on mechanical properties was analyzed. Finally, the microstructures fore and after aging were examined by OM and TEM, and the strengthening mechanism of 1420 Al-Li alloy was further studied. It is found that artificial aging especially two-step aging can increase mechanical properties of post-SPF material obviously, and δ (Al3Li) is the primary strengthening phase.


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