scholarly journals Comprehensive Study of the Influence of the Bonding Temperature and Contact Pressure Regimes during Diffusion Bonding on the Deformation and Mechanical Properties of AISI 304

Author(s):  
Thomas Gietzelt ◽  
Mario Walter ◽  
Volker Toth ◽  
Florian Messerschmidt ◽  
Melina Blem
2014 ◽  
Vol 881-883 ◽  
pp. 1301-1306
Author(s):  
Chaiyoot Meengam ◽  
Prapas Muangjunburee ◽  
Suppachai Chainarong

SSM 356-T6 aluminium alloys generally present low weldability by fusion methods because of the sensitivity to weld solidification cracking, porosities, change microstructure in weld zone and other defects in the fusion zone. Diffusion bonding can be deployed successfully with aluminium alloys. This paper presents the technique to conserve the globular weld structure of SSM 356-T6 aluminium alloy. The effect of joining parameters on the microstructure and mechanical properties of diffusion bonding butt joints of semi-solid metal 356-T6 aluminium alloy were investigated by conditions as follows: contact pressure at 0.4, 0.9, 1.8, 2.4 and 2.7 MPa, for 3 hours holding time and temperature at 495°C under argon atmosphere at 4 liters per minute. The results showed that condition used contact pressure 2.4 MPa, with 3 hours holding time and temperature at 495°C, under argon atmosphere provided. The highest joint strength reaching to 182.2 MPa, which had joint efficiency of 61.34 percents compared with base material. In addition, microstructure in welded zone after welding is still in globular structure, but the grain size was increased when the higher bonding temperature was used. The results of this investigation have shown that an average hardness is around 121.2 HV.


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):  
Thomas Gietzelt ◽  
Volker Toth ◽  
Manfred Kraut ◽  
Uta Gerhards ◽  
Robin Duerrschnabel

Diffusion bonding is often used on pre-machined parts to generate internal cavities, e.g. for cooling injection molding tools close to the mold cavity. Only then, the workpieces are finished to their final dimensions. In the case of micro-process devices, however, it is essential to precisely control the deformation, as otherwise uncontrollable pressure losses will occur with channel cross-sections in the sub-millimeter range. Post-processing is not possible. The most important process parameters for diffusion bonding are temperature, dwell time and contact pressure, with the bonding temperature and contact pressure acting in opposite directions and showing a strong non-linear dependence on deformation. In addition, the deformation is influenced by a number of other factors such as the absolute size of the cross-section and the aspect ratio of the parts, the dimensions and distribution of the internal cross sections and the overall percentage of the cross-section to be bonded. In micro process engineering, small material cross-sections in the range of the materials microstructure can facilitate additional deformation mechanisms such as grain boundary sliding, which are not relevant at all for larger structures. For parts consisting of multiple layers, tolerances in thickness and roughness of multiple surfaces must be levelled, contributing to the percentaged deformation. This makes it difficult, especially in micro process engineering and in single or small series production, to determine suitable joining parameters in advance, which on the one hand do not cause unforeseen large deformations, but on the other hand reliably produce highly vacuum-tight components. Hence, a definition of a fixed percentaged deformation does not work for all kinds of components. This makes it difficult to specify parameters for surely obtain high-vacuum tight parts. For successful diffusion bonding, atoms must diffuse over the bonding planes, forming a monolithic part in which the original layers are no longer visible. Only then, mechanical properties identical to those of the base material, which has been subjected to identical heat treatment, can be achieved. In this paper, the impacts of different material cross section widths as well as of the aspect ratio on deformation were investigated. By accident, it was found that also accuracy of the temperature measurement may have a serious impact in terms of deformation.


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.


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.


Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1437
Author(s):  
Zeming Wang ◽  
Xu Yang ◽  
Jing Wang ◽  
Zhonglin Xiao ◽  
Fugong Qi ◽  
...  

The development of welding technology for zirconium alloy has great significance on the safety, stability, and reliability of the operation of the nuclear reactor. In this work, vacuum diffusion bonding of Zr-4 alloy was studied at the diffusion temperature ranging from 760 to 820 °C with holding times of 30–90 min. The effects of diffusion bonding temperature and holding time on the interfacial microstructure and mechanical properties of the diffusion bonded Zr-4 alloy joints were investigated in detail, and the relationship between the interfacial microstructure and shear strength of the diffusion bonded joints was discussed. The results show that the interface bonding ratio of the diffusion bonded Zr-4 joint gradually increased from 74% to 95% with the increasing of bonding temperature. In addition, the grain size of the base material became a larger and brittle second phase composed of Zr(Cr, Fe)2 and eutectic α-Zr + Zr(Fe, Cr)2 formed in the joint with the increase of the temperature as well as the extension of the bonding time. The highest shear strength of 349 MPa was obtained at 800 °C for 30 min under 7 MPa, and the crack of the joint was primarily propagated along with the base material rather than the bonded interface.


Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1127
Author(s):  
Shiwei Li ◽  
Xianjun Sun ◽  
Yajie Du ◽  
Yu Peng ◽  
Yipeng Chen ◽  
...  

This study focuses on the diffusion bonding of a CoCrNi-based medium-entropy alloy (MEA) to a DD5 single-crystal superalloy. The microstructure and mechanical properties of the joint diffusion-bonded at variable bonding temperatures were investigated. The formation of diffusion zone, mainly composed of the Ni3(Al, Ti)-type γ′ precipitates and Ni-rich MEA matrix, effectively guaranteed the reliable joining of MEA and DD5 substrates. As the bonding temperature increased, so did the width of the diffusion zone, and the interfacial microvoids significantly closed, representing the enhancement of interface bonding. Both tensile strength and elongation of the joint diffusion-bonded at 1110 °C were superior to those of the joints diffusion-bonded at low temperatures (1020, 1050, and 1080 °C), and the maximum tensile strength and elongation of 1045 MPa and 22.7% were obtained. However, elevated temperature produced an adverse effect that appeared as grain coarsening of the MEA substrate. The ductile fracture of the joint occurred in the MEA substrate (1110 °C), whereas the tensile strength was lower than that of the MEA before diffusion bonding (approximately 1.3 GPa).


Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1061 ◽  
Author(s):  
Hong Bian ◽  
Yuzhen Lei ◽  
Wei Fu ◽  
Shengpeng Hu ◽  
Xiaoguo Song ◽  
...  

In this study, reliable Ti2AlNb/high-Nb-containing TiAl alloy (TAN) joints were achieved by diffusion bonding. The effects of bonding temperature and holding time on the interfacial microstructure and mechanical properties were fully investigated. The interfacial structure of joints bonded at various temperatures and holding times was characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results show that the typical microstructure of the Ti2AlNb substrate/O phase/Al(Nb,Ti)2 + Ti3Al/Ti3Al/TAN substrate was obtained at 970 °C for 60 min under a pressure of 5 MPa. The formation of the O phase was earlier than the Al(Nb,Ti)2 phase when bonding temperature was relatively low. When bonding temperature was high enough, the Al(Nb,Ti)2 phase appeared earlier than the O phase. With the increase of bonding temperature and holding time, the Al(Nb,Ti)2 phase decomposed gradually. As the same time, continuous O phase layers became discontinuous and the Ti3Al phase coarsened. The maximum bonding strength of 66.1 MPa was achieved at 970 °C for 120 min.


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