Superplastic forming and diffusion bonding for honeycomb structure of Ti–6Al–4V alloy

Han, Wenbo; Zhang, Kaifeng; Wang, Guofeng

doi:10.1016/j.jmatprotec.2006.10.041

Cited by 73 publications

(22 citation statements)

References 15 publications

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“…Currently, SPF/DB technology is the main process to form the multilayer structure and it has been widely used. Furthermore, the titanium alloy sandwich is the most widely used multilayer structure in the field of aerospace [3]. However, conventional SPF/DB process has some disadvantages: (1) long DB time at high temperature makes the connection cycle time longer; (2) loading at high ambient temperature (about 900 ∘ C) makes the material performance lower and the forming die service life shorter; (3) long forming time (nearly 18-hour thermal cycle time) including heating and cooling time leads to the high cost and low productivity [4].…”

Section: Introductionmentioning

confidence: 99%

LBW/SPF/DB Combined Processing and Microstructure of TA15 Titanium Alloy Four-Layer Sandwich Structure with Square Grid

Jiang

Liu³

et al. 2014

Advances in Mechanical Engineering

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The process combining laser beam welding, superplastic forming, and diffusion bonding (LBW/SPF/DB) was performed to fabricate the TA15 titanium alloy sandwich structure with square grid. The microstructure of different regions before and after superplastic forming was also analyzed. The results showed that the laser welded joints of core structure own good superplastic formability under the condition that the laser welding parameters were optimized. The microstructure near the fusion line is columnar crystal and inside the columnar crystal the acicular martensite appeared. The heat-affected zone is relatively narrow and with no obvious grain growth. At 925 ∘ C, under the condition that the loading-time curve was optimized, the external outline of the LBW/SPF/DB formed hollow four-layer sandwich structure is clear and the strengthened ribs are upright. It shows good diffusion bonding quality between the ribs and panels. And the bonded ratio between the upright ribs which rely on each other is above 90%. After superplastic forming, the grain size of the TA15 workpiece increases but remains equiaxed grain. The grain size of laser welded joints also significantly grew up, and the heat-affected zone almost disappeared in this zone. The typical cast microstructure of rapid cooling turned to be the deformed microstructure, creating a better overall performance of the two-state organizations.

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Section: Introductionmentioning

confidence: 99%

LBW/SPF/DB Combined Processing and Microstructure of TA15 Titanium Alloy Four-Layer Sandwich Structure with Square Grid

Jiang

Liu³

et al. 2014

Advances in Mechanical Engineering

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“…The superplastic forming and diffusion bonding processes have interesting applications for aerospace components. The complicated structures could be obtained during this process, such as hollow [1,2], with lower cost and weight. Therefore, the process has been applied to form sandwich construction of titanium alloys and aluminum alloys in aerospace [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Effect of hydrogen content on superplastic forming/diffusion bonding of TC21 alloys

Wang

Zhang

Hou

et al. 2010

Journal of Alloys and Compounds

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“…Practical applications of this technology can also be combined with a joining operation involving diffusion bonding (SPF/DB) between several sheets of material. SPF/DB is an efficient process used for fabrication of hollow fan blades [8], honeycomb structures [109], bellows expansion joints [73] and large engine components [110]. A complex hollow structure with net-shape was fabricated from fine-grained sheet by superplastic forming, and the refined structure with a grain size of about 0.4 µm led to a substantial mechanical properties improvement [39].…”

Section: Superplastic Forming Of Titanium Alloysmentioning

confidence: 99%

“…The weight gain for Ti-6Al-4V alloy oxidized in air at 800ºC for 16 min is about 1.2 mg/cm 2 [117]. Conventional superplastic forming of Ti-6Al-4V alloy is usually carried out above 900ºC [8,93,109,243]. For comparison with the oxidation behavior between the conventional SPF and superplastic-like forming, Figure 8 In order to obtain a better understanding of the oxidation in the material, the oxide film that formed at 800ºC was further examined by X-ray diffraction (XRD).…”

Section: Oxidation Behaviormentioning

confidence: 99%

Superplastic-like forming of lightweight alloys

Liu¹

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Conventional superplastic forming (SPF) is attractive for the current industrial fabrication of precision, large and complex-shaped sheet-metal components. This process requires a fine-grained material and is carried out at high temperatures (typically above 500º C for aluminum alloys and 900º C for titanium alloys) and slow forming rates (mostly strain rate slower than 10-3 s-1). To address these limitations, an advanced sheet-forming process has been designed by combining hot drawing and superplastic forming (namely gas forming) in a one-step operation to establish a fast forming technology. The process together with a nonisothermal heating system is referred to as superplastic-like forming. The aim of this work is to investigate (i) the relationship between process parameters, material draw-in and thickness distribution and (ii) the microstructural evolution, deformation mechanism and post-forming properties during forming. Target materials are commercial grade AA5083 and Ti-6Al-4V alloys. Tensile tests were performed for both materials to determine the optimal deformation conditions, i.e. temperature and strain rate. The flow stress data of AA5083 were used in the calibration of a material model for finite element modeling (FEM). The results showed that AA5083 can deform with reasonable flow stress and tensile elongation at 400º C and a strain rate of 2×10-3 s-1 and that Ti-6Al-4V alloy possesses good forming capability at 800º C and a strain rate of 10-3 s-1. A rectangular die cavity with multiple steps was used to demonstrate different amounts of material draw-in and surface expansion of the formed part in superplastic-like forming. The punch geometry was designed and validated through a parametric study during hot drawing. The measured drawing limits were used to determine the sheet ABSTRACT II size for hot drawing. The optimal dimensions of AA5083 and Ti-6Al-4V sheets are 200×200 and 210×210 mm 2 , respectively. The non-isothermal heating system is expected to maintain the sheet at a lower global (furnace) temperature. Meanwhile, a higher local temperature in specific zones, i.e. die radii, ensures that the material there has more ductility to flow. For AA5083, the entire forming was conducted at a global temperature of 400º C, but the material close to the die radii was selectively heated to 420º C. During superplastic-like forming of Ti-6Al-4V alloy, the global and local temperatures were 800 and 820º C, respectively. After completion of forming AA5083 in 8 min, a final part with maximum percentage thinning of 40% at the outward corners and 137% surface expansion was achieved. The forming of Ti-6Al-4V alloy was completed in 16 min, exhibiting a maximum percentage thinning of 54% at the outward corners and the surface expansion of 130%. Stress gradients and the corresponding strain rate differences at the outward corners in the forming sheet led to thinning gradient and plastic straining as a result of geometric inhomogeneity as demonstrated through finite element simulations of hot drawing and gas formi...

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Superplastic forming and diffusion bonding for honeycomb structure of Ti–6Al–4V alloy

Cited by 73 publications

References 15 publications

LBW/SPF/DB Combined Processing and Microstructure of TA15 Titanium Alloy Four-Layer Sandwich Structure with Square Grid

LBW/SPF/DB Combined Processing and Microstructure of TA15 Titanium Alloy Four-Layer Sandwich Structure with Square Grid

Effect of hydrogen content on superplastic forming/diffusion bonding of TC21 alloys

Superplastic-like forming of lightweight alloys

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