Industrial Applications of Rheoforming Technology in China

Rheological forming, a semi-solid metal forming process, is one of the manufacturing technologies for near net shape forming. The technology has attracted global academic research interests in recent years. This paper presents the current status of industrial applications of the semi-solid rheological forming technology in the China mainland. A variety of semi-solid slurry preparation techniques have been adopted including electromagnetic stirring and low superheat pouring. Dedicated semi-solid rheological forming equipment developed by the local manufacturers have been highlighted. This paper also makes an attempt to review the crucial factors for successful industrial application of the semi-solid metal forming process.

Rheological Constitutive Model Depending upon Temperature and Strain Rate of Sheet TC1 Titanium Alloy

In order to achieve the numerical calculating rheological forming process of materials, a series of tension experiments under the different temperatures and different strain rates were done on the standard samples of sheet TC1 titanium alloy. The experimental results were analyzed theoretically and the rheological stress constitutive models of TC1 titanium alloy are built combining the strong points of the Perzyna model and Johnson-Cook model. Comparing the calculation results conducted from the model with the experimental results, it proves that the model can reflect the temperature effect and strain rate effect of TC1 titanium alloy.

Research on Creep Constitutive Model of TC11 Titanium Alloy Based on RBFNN

The paper is aimed to exploit a creep constitutive mode of TC11 titanium alloy based on RBF neural network. Creep testing data of TC11 titanium alloy obtained under the same temperature and different stress are considered as knowledge base and the characteristics of rheological forming of materials and radial basis function neural network (RBFNN) are also combined when exploiting the model. A part of data extracted from knowledge base is divided into two groups: one is learning sample and the other testing sample, which are being performed training, learning and simulating. Then predicting value is compared with the creep testing value and the theoretical value deduced by primary model, which validates that the RBFNN model has higher precision and generalizing ability.

Continuous Rheological Forming of A6061 Wrought Aluminum Alloy by Using Helical Shape Stirrer and its Thixoforging Process

Interest in the rheology forming technology for fabrication of light weight materials and for resolving environmental issues has been growing in industrial and academic society. In this study, the helical shape stirrer was designed to produce rheological material. The experimental variables, which were stirring time 0-1200 sec, stirring velocity 0-100 rpm and melt temperatures for semisolid states, were established. The rheological materials were produced under established experiment conditions, and then mechanical properties were measured. Sequence-production equipments were appended to fabrication system of rheology material to make rheology materials continuously. Therefore, the development of sequence-production system equipped with a specially designed mechanical stirrer in spiral shape was necessary for fabricating fine grains and their uniform globular rheology materials. The thixoforging was experimented with rheological A6061 wrought aluminum alloy fabricated by the spiral shape stirrer. Microstructural morphology of the forged samples was investigated and their mechanical properties characterized.

Research on the Effect of Entry Angle and Pressure-Pad Force on Deep-Draw Thermo-Rheological Forming of a TC1 Ti-Alloy Sheet

Numerical simulation can be successfully applied to evaluate product manufacturability and predict, while material wrinkling and splitting are associated with entry angle and pressure-pad force during sheet metal stamping process. In this paper, the influence of entry angle and pressure-pad force on deep-drawing thermal forming of TC1 titanium alloy was analyzed by using explicit dynamic finite element software STAMPACK, two kinds of main invalidation, including wrinkling and splitting, and obtained that the entry angle is an important factor for deep-draw thermal forming. By analyzing the forming operation and optimizing the entry angle and the pressure-pad force of the die, the best range of the entry angle and the suitable pressure-pad force without wrinkling were obtained and splitting phenomena were controlled effectively. The researched results of numerical simulation provided some parameters for die design.