Forming Of Titanium Alloy Research Articles

Development of finite element models of gas forming process of Ti alloys structures

The use of combined technology of gas forming and solid-phase pressure bonding for manufacturing large-diameter torus billets with diameter up to 1500 mm, wall thickness up to 8 mm, and diameter in cross-section up to 400 mm from titanium alloys for manufacturing of pipeline bends of desired size is shown. The technologymaes it possible to reduce production costs by increasing the productivity of the manufacturing process and applying new design and technological solutions. The possibility of using the SIMULIA Abaqus software package for modeling gas forming of titanium alloys in superplasticityconditions with non-uniform heating of the billets is considered. The method of combined thermo mechanical analysis (COUPLED TEMP-DISPLACEMENT) with inclusion of the creep effect was used.

Prediction of tri-modal microstructure under complex thermomechanical processing history in isothermal local loading forming of titanium alloy

Abstract To control the tri-modal microstructure and performance, a prediction model of tri-modal microstructure in the isothermal local loading forming of titanium alloy was developed. The staged isothermal local loading experiment on TA15 alloy indicates that there exist four important microstructure evolution phenomena in the development of tri-modal microstructure, i.e., the generation of lamellar α, content variation of equiaxed α, spatial orientation change of lamellar α and globularization of lamellar α. Considering the laws of these microstructure phenomena, the microstructure model was established to correlate the parameters of tri-modal microstructure and processing conditions. Then, the developed microstructure model was integrated with finite element (FE) model to predict the tri-modal microstructure in the isothermal local loading forming. Its reliability and accuracy were verified by the microstructure observation at different locations of sample. Good agreements between the predicted and experimental results suggest that the developed microstructure model and its combination with FE model are effective in the prediction of tri-modal microstructure in the isothermal local loading forming of TA15 alloy.

Current assisted superplastic forming of titanium alloy

Current assisted superplastic forming combines electric heating technology and superplastic forming technology, and can overcome some shortcomings of traditional superplastic forming effectively, such as slow heating rate, large energy loss, low production efficiency, etc. Since formability of titanium alloy at room temperature is poor, current assisted superplastic forming is suitable for titanium alloy. This paper mainly introduces the application of current assisted superplastic forming in the field of titanium alloy, including forming technology of double-hemisphere structure and bellows.

Current Status of Research and Development on Superplasticity at the Institute for Metals Superplasticity Problems

Principles of fabrication of ultrafine grained bulk and sheet materials for superplastic deformation by the methods of multiple isothermal forging and warm rolling are formulated. New data on superplastic behaviour of commercial alloys, on diffusion bonding of similar and dissimilar materials, and superplastic forming of titanium alloys are presented. The recent application of the diffusion bonding and superplastic forming technology for the production of hollow blades is demonstrated.

The 3D Modeling of Dies Based on UG and Numerical Simulation of the Heat Rheological Forming of Titanium Alloy Vane Disk

The heat rheological forming of the TC11 titanium alloy vane disk has been studied. The dies of rheological forming were 3D-modeled based on UG and the heat rheological forming of the TC11 titanium alloy under a certain temperature and a low strain rate was analyzed by DEFORM 3D based on variation principle of rigid viscoplastic non-compressed material. A series of results including rheological forming procedure, equivalent strain field, temperature field and load-stroke curves of punch and cavity die, were obtained by finite element method. The deformation characteristic of the TC11 titanium alloy was well known and its heat rheological forming process and parameters were determined. Moreover, the local underfilled phenomenon in practical manufacture was predicted and analyzed, and we found that the defects could be restricted by reducing the forming velocity.

ENAMEL GLASSES AS LUBRICANTS FOR FORMING SHEET METAL

The NEED OF THE AIRCRAFT INDUSTRY for structural alloys having high strength‐to‐weight ratios above 500°F. and the availability of new titanium alloys having these properties has presented some new and difficult manufacturing problems. Examination of representative titanium alloys over a wide temperature range shows that at room temperature the yield strength is high and that the difference between yield and ultimate strengths is quite small. This presents difficult conditions for sheet metal forming operations such as drawing, hammer forming, and drawbench forming. Since a high percentage of aircraft parts are formed from sheet metal, and since good formability is of great importance, consideration has been given to forming these parts at elevated temperatures where the properties affecting forming are more suitable. Above 800°F the yield strength of the alloy is much lower and the spread between yield and ultimate is greater. Exploratory work on the forming of titanium alloys at 800°F–1,400°F has shown formability to be satisfactory. However, serious galling of the titanium alloys occurred and hitherto conventional forming lubricants were proved quite unsatisfactory due to temperature. The severe galling was not only ruinous to the parts formed, but scored the dies badly and necessitated refinishing of the dies between operations. This galling occurs whenever titanium alloys rub against themselves or other metals.