Numerical Simulation and Technical Study on Superplastic Forming/Diffusion Bonding for Multi-sheet Structure of Ti2AlNb Alloy

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.

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Scanning Acoustic Microscopy for Quantitative Analysis of Superplastic Forming Diffusion Bonding of Titanium Aerospace Components

Ultrasonics International 93 ◽

10.1016/b978-0-7506-1877-9.50015-9 ◽

1993 ◽

pp. 53-56

Author(s):

Françoise THEVENOT ◽

Norbert FRESTEL ◽

Alain LIOT ◽

Hervé TRETOUT ◽

René DE MOL

Keyword(s):

Quantitative Analysis ◽

Diffusion Bonding ◽

Superplastic Forming ◽

Acoustic Microscopy ◽

Scanning Acoustic Microscopy

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Spark Plasma Diffusion Bonding of TiAl/Ti2AlNb with Ti as Interlayer

Materials ◽

10.3390/ma13153300 ◽

2020 ◽

Vol 13 (15) ◽

pp. 3300

Author(s):

Boxian Zhang ◽

Chunhuan Chen ◽

Jianchao He ◽

Jinbao Hou ◽

Lu Chai ◽

...

Keyword(s):

Tensile Strength ◽

Base Metal ◽

Diffusion Bonding ◽

Energy Dispersive Spectrometer ◽

Tensile Tests ◽

Slow Cooling ◽

Ti2alnb Alloy ◽

Heat Treated ◽

Plasma Diffusion ◽

Spark Plasma

To solve the problem of poor weldability between TiAl-based and Ti2AlNb-based alloys, spark plasma diffusion bonding was employed to join a TiAl alloy and a Ti2AlNb alloy with a pure Ti foil as interlayer at 950 °C/10 KN/60 min. After welding, slow cooling was carried out at a rate of 5 °C/min, followed by homogenization at 800 °C for 24 h. The microstructural evolution and elemental migration of the joint were analyzed via a scanning electron microscope equipped with an energy dispersive spectrometer, while the mechanical properties of the joint were assessed via microhardness and tensile tests. The results show that the spark plasma diffusion bonding formed a joint of TiAl/Ti/Ti2AlNb without microcracks or microvoids, while also effectively protecting the base metal. Before heat treatment, the maximum hardness value (401 HV) appeared at the Ti2AlNb/Ti interface, while the minimum hardness value (281 HV) occurred in the TiAl base metal. The tensile strength of the heat-treated joint at room temperature was measured to be up to 454 MPa, with a brittle fracture occurring in the interlayer. The tensile strength of the joint at 650 °C was measured to be up to 538 MPa, with intergranular cracks occurring in the TiAl base metal.

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