Papers by Keyword: Super Plastic Forming (SPF)

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Authors: Gang Wang, Jun Chen, X.Y. Ruan
Abstract: The complex superplastic forming (SPF) technology applying gas pressure and compressive axial load is an advanced forming method for bellows made of titanium alloy, which forming process consists of the three main forming phases namely bulging, clamping and calibrating phase. The influence of forming gas pressure in various phases on the forming process are analyzed and models of forming gas pressure for bellows made of titanium alloy are derived according to the thin shell theory and plasticity deformation theory. Using model values, taking a two-convolution DN250 bellows made of Ti-6Al-4V titanium alloy as an example, a series of superplastic forming tests are performed to evaluate the influence of the variation of forming gas pressure on the forming process. According to the experimental results models are corrected to make the forming gas pressures prediction more accurate.
3051
Authors: T. Usugi, N. Akkus, Masakazu Kawahara, H. Nishimura
735
Authors: Zhi Qiang Li, He Ping Guo
Abstract: As a versatile fabrication process for titanium and aluminum alloys, SPF/DB offers a real potential for revolutionizing aerospace component design. In this paper, the principle, advantages, techno-economics of the process, as well as its application in aerospace industry are introduced. The current trends and the factors relating to the process’s developments are given.
3037
Authors: Shinichi Yajima, M. Shimanuki, Toshimichi Ogisu, Shigeru Kimura, Hideto Oyama
277
Authors: Jie Shao, He Ping Guo, Zhi Qiang Li, X.Q. Han
Abstract: This paper deals with the cavity formation and growth behavior of fine-grained 1420 Al-Li alloy during superplastic forming. The results indicated that there were many sub-micron cavities pre-existing at the particle-matrix interface and these sub-micron cavities grew initially under deformation. Different from uniaxial tension, the cavities nucleation under biaxial tension was combinable effect of stress concentration and matrix/particle de-cohesion. With the strain and temperature increasing, the total number and the average size of cavities increased. By the calculations, it was seen that diffusional growth process dominates the initial stage of void growth, and for void radii>~1.7μm, void growth was mainly controlled by plasticity.
633
Authors: Gennady A. Salishchev, Oleg R. Valiakhmetov, R.M. Galeyev, F.H. Froes
441
Authors: X.F. Xu, L.M. Tang, G.Q. Tong
Abstract: A comparative study of different element formulations in simulating superplastic forming with the MARC finite element code is performed in the paper. Simulations were accomplished with solid, shell, membrane elements to predict forming characteristics and pressure-time curves. Finite element analysis (FEA) predictions of SPF pressure-time curves were found to be greatly affected by the element type and the strain rate control algorithms. Two strain rate control algorithms were applied in the present study: an algorithm based on limiting the rate of deformation with the average strain rate of all the elements, i.e. the build-in method in MARC, and a second algorithm which limits the rate of deformation based on the average strain rate of the elements with the 20 highest strain rates. The resulting pressure-time curves for each of these formulations were compared with respect to each type of element. Under the guide of the analysis, the die was fabricated and the AA5083 bracket was successfully manufactured. Good agreement was obtained between predicted and measured thickness in the part.
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