School of Mechanical, Materials and Mechatronic Engineering
SEMINAR Deformation Mechanisms of near-β Ti Alloys
PRESENTER Mr. Pouyan Naseri WHERE BLD 8-114 DATE Wednesday 24th of August 2016 TIME 12:30-13:30
ABSTRACT Near-β Ti alloys has received considerable attention in aeronautical applications due to the outstanding combination of strength and toughness. This class of Ti alloys respond to heat treatment that allows manufacturers to tailor the required mechanical properties in different solution treated and aged (STA) conditions. They accommodate deformation by multiple mechanisms including dislocation glide, twinning and formation of stress-induced martensite (SIM). The aim of this study is to understand the effect of strain path on the deformation behaviour of near-β Ti alloy and also to explain the sequence of operating deformation mechanisms. In this study, a Ti-10V-3Fe-3Al alloy was produced via BEPM and a bi-modal microstructure was developed by solution treatment followed by ageing in α+β phase field at two distinct temperatures. The effect of microstructure on deformation behaviour was investigated by conducting tensile and a series of interrupted compression tests. The microstructure was analysed using optical and scanning electron microscopy. Results indicate that the microstructures comprise equiaxed β grains with α preferentially nucleated on the β grain boundaries. Some stress-induced products (SIPs) appeared on the microstructure after deformation. At higher strains, the density of SIPs and the number of grains containing them increase simultaneously. Further straining resulted in the emergence of intersecting thin lines and formation of secondary deformation products within the initial thick laths. The engineering stress-strain curves (in compression test) showed a stress plateau which is related to the formation of twins, stress-induced martensite or both. Triggering stress associated with this plateau was higher in the sample heat treated at 625 °C due to the higher stability of the β phase resulted from the enrichment with β-stabilizers and smaller β domain size.
ABOUT THE SPEAKER Pouyan Naseri completed the bachelor degree in industrial metallurgy in 2005 in Azad University (Iran). Then, He graduated my master degree in materials' characterisation from Sharif University of Technology (2007). Currently He is a PhD candidate at School of Mechanical, Materials and Mechatronic Engineering, but located at the Electron Microscopy Centre (EMC), Australian Institute of Innovative Materials (AIIM)http://aiim.uow.edu.au/. My supervisors are Professor Elena Pereloma and Dr. David Mitchell. He is focusing my studies on the phase transformation in near-β Ti alloy with the specific interest in the deformation-induced phase transformations.
Dr. Hongtao Zhu
School of Mechanical Materials and Mechatronic Engineering
Faculty of Engineering and Information Sciences
University of Wollongong, Australia
Eis_academics mailing list Eis_academics@mailman.uow.edu.au http://mailinglists.uow.edu.au/mailman/listinfo/eis_academics