Study On Optimization Of Deformation Parameters And Ring Rolling Simulation Of Ti₂AlNb Alloy

Ring rolling technology is an advanced plastic forming technology capable of producing seamless ring parts of different sizes and cross-sectional shapes.Ring rolling technology has many significant advantages over other ring production technologies,such as low production costs,material savings,small equipment footprint,and excellent product performance,etc.It is the preferred manufacturing technology for all types of seamless rings,and is widely used in industrial fields such as aerospace engines,petrochemicals,and wind power.Ti₂AlNb alloys are as capable as traditional heavy nickel-based high-temperature alloys for long-term use in high-temperature environments and have many advantages such as low density,high specific strength,and specific stiffness,excellent creep resistance at high temperatures,and low coefficient of thermal expansion.Therefore,Ti₂AlNb alloys have broad application prospects in key industrial fields such as space shuttles and satellites and are seen as one of the preferred alloy materials to replace traditional heavy nickel-based alloys.Thus,it seems that Ti₂AlNb alloy ring parts have a very broad application prospect.Since the ring rolling process is a highly nonlinear and nonstationary process,it makes the Ti₂AlNb alloy ring parts prone to defects such as end depressions and ellipses during the rolling process.Therefore,it is particularly important to study the influence law of different process parameters on the rolling process of Ti₂AlNb alloy ring parts.In this paper,a Ti₂AlNb alloy with an atomic ratio of Ti-22Al-23Nb was studied,and thermal compression experiments were conducted using a Gleeble-1500D thermal simulation tester,focusing on the thermal deformation behavior of the Ti₂AlNb alloy.Based on the hot compression experiments,the finite element model of Ti₂AlNb alloy diameter-axial ring rolling and Ti₂AlNb alloy material library were established,and the simulation of the diameter-axial ring rolling was carried out by using Simufact Forming finite element software and the simulation results were correlated and analyzed.The specific study of this paper is as follows:(1)The isothermal constant strain rate thermal compression experiments were conducted using Gleeble-1500D thermal simulation tester to study the high temperature deformation behavior of Ti₂AlNb alloy under the deformation temperature of 1273-1423K and strain rate of0.001-10s^-1,and the stress-strain data of Ti₂AlNb alloy under different deformation conditions were extracted;Modeling of the instanton equations of Ti₂AlNb alloys based on the Arrhenius hyperbolic sine function equation;The effect laws of different deformation parameters on the strain rate sensitivity index m and strain hardening index n of Ti₂AlNb alloys were investigated;Finally,the thermal processing diagram of Ti₂AlNb alloy at a true strain of 0.9 was established.By analyzing the thermal processing diagram and microstructure,the range of thermal processing process parameters for the destabilized rheological zone as well as the better thermal processing region were clarified.(2)Simulation analysis of the rolling process of Ti₂AlNb alloy radial-axial rings was carried out using Simufact Forming finite element software to investigate the effects of different initial ring billet temperatures,different core roll feed rates,and different ring billet sizes on the strain field,temperature field,forming accuracy and driving roll rolling force of Ti₂AlNb alloy rings.At the same time,the possible defects in the rolling process of Ti₂AlNb alloy diameter-axial rings are predicted and analyzed,and the corresponding countermeasures are given.