The Theoretical,Experimental & Practical Research On Rheological Forming Of Metals

The theory of rheological forming, a deformation theory of greater universal significance, has been developed recent years based on the theories of plastic forming, superplastic forming and creep forming. It is the practical application of rheology to plastic working field. The theory is being widely accepted and applied to scientific research as well as production practice, and is showing its strong vitality and practical prospect.With a hoverplane titanium alloy axial flow impeller and an antitank missile cylindrical shell as the research background, various inquiries on rheological forming theory, experiments and application have been studied under the direction of rheological mechanics in this paper.Firstly, based on internal variable theory, the first and second law of thermodynamics, thermo-dynamical analysis has been done for irreversible process of metal's rheological forming. The necessary condition of the irreversible deformation process has been derived.Secondly, the relationship has been set up for the first time between the microstructural evolution theory of dislocation density and internal variable theory indicating the macroscopic rheological behavior of metals by combining the macroscopic appearances and microstructure. In the same time, the chaotic dynamic theory has been applied creatively to analyze the engineering practical problems of metal's rheological forming.Thirdly, the creep experiments under high temperature has been done on the aluminum alloy Lc4. The integral kernel of the creep indicating the rheological properties of viscoplasticity has been achieved through the experiments. The relaxation kernel has also been derived by the Laplace transformation.Furthermore, the numerical simulation of rheological forming process has been conducted in many aspects. The simulation results form an important basis for the optimum designing of die parameters and technological parameters of rheological forming, and provide a way for inverse design of rhelolgical forming. Some simulation results not only coincided with the practical product, but also testified to some theoretical results.Finally, the mechanical properties and the metallographic structures of the machine parts have been surveyed and analyzed. The results show that the internal quality and mechanical property of the parts produced by Theological forming, have been improved obviously compared with that of the traditional producing method,.In conclusion, we believe that the work of this paper will promote the research and development of plastic deformation theory, and will also promote the reforming of forming technologies and methods effectively.