Titanium alloys usually need to be hot processed in phase 1 or phase 2 to obtain products with certain microstructure and properties.The selection of thermal processing parameters has an important influence on the machining properties and microstructure of titanium alloys.In recent years, more and more research has been done in the field of thermal processing of titanium alloys in China, among which thermal simulation and numerical simulation technology have been especially applied in the mechanism of thermal deformation and the law of microstructure evolution of titanium alloys.
Titanium alloys have been widely used in the fields of aerospace because of their excellent properties such as low density, high specific strength and creep resistance.Titanium alloy has the characteristics of low ductility, deformation resistance and anisotropy, so titanium alloy is very sensitive to thermal deformation process parameters.In this paper, physical simulation and numerical simulation techniques and their applications in the thermal processing of titanium alloys are introduced.This paper focuses on the application of simulation technology in the thermal deformation mechanism of titanium alloys, the prediction and control of defect generation and microstructure evolution.
With the close combination of traditional plastic machining technology and modern computer technology, the traditional empirical design method is replaced by analog design quickly and effectively.Predictive data or results are required before plastic forming processes are designed and determined, and process simulation is usually required.The simulation before the actual production is generally divided into physical simulation and numerical simulation.Typical applications of thermal simulation techniques.
1. Many scholars have conducted thermal compression and deformation experiments on different types of titanium alloy by means of thermal/force simulation testing machine, and obtained the flow stress curve of the material, namely the stress-strain relationship.The flow stress curve reflects the internal relationship between the flow stress and the deformation process parameters, and is also a macroscopic manifestation of the change of the internal structure of the material.A constant strain rate compression deformation test was carried out on a thermal simulator to study the dynamic thermal deformation behavior of TA15 titanium alloy.Dynamic recrystallization is the main softening mechanism in the zone of phase, while dynamic recovery is the main softening mechanism in the zone of phase.As the deformation rate decreases.
2. Typical application of numerical simulation technology.Due to the numerical simulation technology can truly make titanium alloy hot working process on the computer, so enterprise producers and researchers are using the ideal process parameters and the corresponding technology research organization, the relationship between mechanical properties, to optimize the existing production process and lower the new products, new technology, new material of the purpose of the development costs.The phase evolution of flake TC21 titanium alloy in two-phase forging was studied.The variation law of temperature field and strain field in forging process was simulated and analyzed.The results show that the strain field and temperature field influence the evolution of sheet phase. Under the low strain condition, the temperature of the forging edge decreases rapidly, recrystallization is sufficient, and the temperature of the forging center is high.
The diversity of microstructure of titanium alloy has a regular relation with the production process of titanium alloy and the diversity of each working procedure.It is difficult to predict and control the microstructure and properties of titanium alloys by traditional methods.With the development of computer and numerical simulation technology in recent years, the numerical simulation method of microstructure has become a powerful tool to obtain the quantitative relationship of the influence of main process parameters on the macroscopic and microscopic microstructure of the hot forming workpiece.Using numerical simulation technology to reproduce the evolution process of microstructure can not only deepen the understanding of the mechanism of microstructure change, promote the development of existing theories, but also improve the microstructure of materials and optimize the preparation process of materials, so as to obtain the expected mechanical energy of materials.