CHANGE IN MICROSTRUCTURE OF HEAT TREATED TI-6AL-4V ALLOY IN DIFFERENT TEMPERATURES AND STRAIN RATE

Abstract

Aviation industry is growing day by day and with increase in globalization and growth of overseas trade, it is bound to enhance and develop more on the future. Many more design and manufacturing techniques will need to be changed to improve the operational parameters in aircrafts. These various components of the aircraft engines are manufactured using titanium and the process involved is forging. Forging processes are those manufacturing processes which make use of suitable stresses (like compression, tension, shear or combined stresses) to cause plastic deformation of the materials to produce the required shapes. It may be hot or cold forging processes, which involves heating or striking the material at atmospheric or high temperatures in order to get the desired shapes and sizes. Present research aimed to simulate those hot forging process for titanium alloy at a laboratory level and observe the changes in the microstructure of the titanium alloy with change in temperature and also to then validate the simulation results with a finite element based software, also to observe the effect of friction coefficient between the dies and the sample and their effect on the microstructure. The microstructure is based on the Strain, Strain Rate and Temperature given at the time of the hot forging. These factors need to be varied in order to observe the change in microstructure under different conditions also, to observe the effect of friction coefficient on the microstructure. Once compressed, the sample was sectioned, polished and then viewed under optical Microscope at various zoom levels to observe the changes in the microstructure of the alloy. The Temperature variations and the Force – Stroke graphs obtained from the GLEEBLE 3800 machine during the thermo mechanical compression have been validated using the finite element based software DEFORM 2D.