scholarly journals Diffusion Bonding of Ti2AlNb Alloy and High-Nb-Containing TiAl Alloy: Interfacial Microstructure and Mechanical Properties

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1061 ◽  
Author(s):  
Hong Bian ◽  
Yuzhen Lei ◽  
Wei Fu ◽  
Shengpeng Hu ◽  
Xiaoguo Song ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Diffusion Bonding ◽  
Tial Alloy ◽  
Energy Dispersive Spectrometer ◽  
Bonding Temperature ◽  
Interfacial Microstructure ◽  
Holding Time ◽  
Interfacial Structure ◽  
Microstructure And Mechanical Properties ◽  
O Phase

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.

scholarly journals Microstructure and Mechanical Properties of Vacuum Diffusion Bonded Zr-4 Alloy Joint

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1437
Author(s):  
Zeming Wang ◽  
Xu Yang ◽  
Jing Wang ◽  
Zhonglin Xiao ◽  
Fugong Qi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Diffusion Bonding ◽  
Nuclear Reactor ◽  
Bonding Temperature ◽  
Base Material ◽  
Interfacial Microstructure ◽  
Second Phase ◽  
Microstructure And Mechanical Properties ◽  
Diffusion Temperature

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.

Vacuum diffusion bonding W to W-Cu composite: Interfacial microstructure and mechanical properties

Vacuum ◽  
2019 ◽  
Vol 165 ◽  
pp. 19-25 ◽  
Author(s):  
Haixiang Yan ◽  
Jinglian Fan ◽  
Yong Han ◽  
Qing Yao ◽  
Tao Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Diffusion Bonding ◽  
Interfacial Microstructure ◽  
Microstructure And Mechanical Properties

scholarly journals Improvement for Interfacial Microstructure and Mechanical Properties of Ti3SiC2/Cu Joint Brazed by Ag-Cu-Ti Filler with Copper Mesh

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 401
Author(s):  
Haiyan Chen ◽  
Xin Nai ◽  
Shuai Zhao ◽  
Decai Lu ◽  
Zhikang Shen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Coefficient Of Thermal Expansion ◽  
Interfacial Microstructure ◽  
Holding Time ◽  
Interface Microstructure ◽  
Microstructure And Mechanical Properties ◽  
The Difference ◽  
Maximum Shear Strength ◽  
Copper Mesh

Ti3SiC2 ceramic and copper were successfully vacuum brazed using Ag-Cu-Ti filler and Ag-Cu-Ti filler with copper mesh, respectively. In this study, the effects of copper mesh and brazing parameters on the interface microstructure and mechanical properties of the joints were systematically studied. The results revealed that the typical interfacial microstructure of joint was Ti3SiC2 ceramic/Ti5Si3 + TiC + Ti2Cu + Ti3Cu/Ag (s, s) + Cu (s, s)/eutectic Ag-Cu + TiSiCu/Cu. A maximum shear strength of joint obtained at a brazing temperature of 870 °C and a holding time of 10 min can reached up to 66.3 ± 1.2 MPa, which was 34.7% higher than that without copper mesh. The improvement of mechanical property was attributed to the extraordinary plasticity of copper mesh, which reduced the residual stress caused by the difference in the coefficient of thermal expansion at the interface of joints. As the brazing temperature and holding time further increased, the shear strength of joints decreased due to the excessively thick reaction layer of intermetallic compounds.

Investigation on Mechanical Properties and Microstructure of SSM 356-T6 Aluminium Alloy by Diffusion Bonding

2014 ◽  
Vol 881-883 ◽  
pp. 1301-1306
Author(s):  
Chaiyoot Meengam ◽  
Prapas Muangjunburee ◽  
Suppachai Chainarong
Keyword(s):  
Mechanical Properties ◽  
Aluminium Alloy ◽  
Contact Pressure ◽  
Diffusion Bonding ◽  
Aluminium Alloys ◽  
Bonding Temperature ◽  
Weld Zone ◽  
Base Material ◽  
Argon Atmosphere ◽  
Holding Time

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.

scholarly journals Microstructure and Mechanical Properties of Diffusion-Bonded CoCrNi-Based Medium-Entropy Alloy to DD5 Single-Crystal Superalloy Joint

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1127
Author(s):  
Shiwei Li ◽  
Xianjun Sun ◽  
Yajie Du ◽  
Yu Peng ◽  
Yipeng Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Single Crystal ◽  
Diffusion Zone ◽  
Diffusion Bonding ◽  
Bonding Temperature ◽  
Single Crystal Superalloy ◽  
Interface Bonding ◽  
Microstructure And Mechanical Properties ◽  
Joint Diffusion

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).

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