A Study on Variation of Microstructural Parameters in Titanium Alloys during near Superplastic Regime of Deformation

Abstract

Deformation of Titanium alloys close to optimal superplastic condition i.e. near superplastic regime of deformation leads to significant change in microstructures.VT-9 titanium alloy was used in order to find out those parameters of microstructure which are varying significantly during near superplastic regime of deformation. Tensile tests were carried out at 930°C up to fracture with a constant strain rate of 5*10-4 s-1 and a jump wise varying strain rate of 1*10-4 s-1 & 5*10-4 s-1 .The microstructural parameters of both air-cooled and water quenched portion i.e. size of alpha phase, percentages of alpha phase and parameter of non-uniaxiality of alpha phase were found to change significantly during near superplastic regime of deformation. It has been found that in the near superplastic regime of deformation percentage of α-phase decreased from 90% to 13%. As the β-transus temperature of this alloy is 970°C, this significant change in percentage of α-phase is attributed to deformation induced phase transformation. Optical microscopes, micro Vickers hardness test, XRD, FESEM have been used to characterize the microstructure of the material.

First-principles calculation on LaAlO3 as the heterogeneous nucleus of TiC

“…Because of its high hardness and wear resistance, Fe-Cr-C-Ti alloy has been widely applied in metallurgical, mineral and cement industries [1][2][3]. According to its microstructure, the Fe-Cr-C-Ti alloy can be divided into hypoeutectic, eutectic and hypereutectic ones, and the microstructure is mainly composed of martensite and complex carbides, such as MC, M 7 C 3 and M 23 C 6 [4,5].…”

Experimental study on microstructural variation in near alpha titanium alloy during non-optimal regime of superplastic deformation

“…9 In superplastic forming industry, deformation process is carried out not at optimal but closes to the boundary of optimal superplastic condition that is called near superplastic regimes for which microstructure changes significantly during the deformation process. 11 For computer simulation of these industrial processes, it is very much essential to develop a constitutive equation that can also take into account the major changes in microstructure that takes place during non-optimal process of superplastic deformation. It has already been reported that the average grain size of Ti-6Al-4V titanium alloy changed from its initial value during non-optimal regime of superplastic deformation.…”

“…In real technological application, maintenance of these narrow ranges of condition required for optimal superplastic flow from beginning to end is a very difficult and challenging task 9. In superplastic forming industry, deformation process is carried out not at optimal but closes to the boundary of optimal superplastic condition that is called near superplastic regimes for which microstructure changes significantly during the deformation process 11. For computer simulation of these industrial processes, it is very much essential to develop a constitutive equation that can also take into account the major changes in microstructure that takes place during non-optimal process of superplastic deformation.…”