Invited Speaker

Assoc. Prof. Xiu Song

Northeastern University

E-mail: songxiu@mail.neu.edu.cn

Title:

Strengthening and Toughening Mechanisms of Titanium Alloys via the Combined Process of Deformation and Teat Treatment

Profile:

Xiu Song, associated Professor in school of materials science and engineering of Northeastern University, graduated from Northeast University with a major of Materials Science in 2011. She has done the cooperative research as a research doctoral student at Institute for Materials Research (IMR), Tohoku University, Japan for two years from 2008 to 2010, and been in Aalborg University, Denmark as a visit researcher for half a year from Aug. 2018 to Jan. 2019. Her research is mainly focused on the microstructure evolution and strengthening-toughening mechanisms of advanced structural materials including superalloy and biomedical titanium alloy by plastic deformation and heat treatment, and mechanical behavior evaluation of advanced structural materials in simulated service environment. She has finished more than 10 scientific and technological research projects including the National Nature Science Foundation of China, the Natural Science Foundation of Liaoning Province, the Ministry of Education Funds, and so on. She has published more than 20 academic papers which is ranked in JCR Q1 as the first author or corresponding author, and 2 national invention patents authorized. She has won the third prize of Liaoning Province Natural Science Academic Achievement and the third prize of Shenyang Natural Science Academic Achievement. And she has obtained the first prize of Liaoning Province Science and Technology Progress in 2025.

Abstract:

Titanium and titanium alloy with relative low Yong’s modulus, good corrosion resistance and excellent biocompatibility, has been widely used as one kind of promising biomaterials, such as artificial endovascular stents, bone plates, and dental implants. But the strength of pure titanium and β titanium alloy is relative lower than that of α+β titanium alloy. The improvement in strength and ductility of pure titanium and new developed β titanium alloy has been successfully obtained through the combined process of deformation and heat treatment, and the strengthening-toughening mechanisms has been investigated by TEM and EBSD. The results show that the good match of tensile strength and elongation of pure titanium has been obtained through an optimized process including constrained groove pressing and intermediate heat treatment between 673 K and 873K among different pressing passes. The improvement in strength by above 60% compared with that of pure titanium is ascribed to the more dislocation tangles near the sub-grains which from during the annealing at lower temperature, and the twin variants activated during the process combined the deformation and heat treatment. The tensile strength of b Ti-29Ta-13Nb-4.6Zr (TNTZ) is highly enhanced by above 80% without losing plasticity so much which is still longer than 10%, via cold rolling and cryogenic rolling followed with short-time aging between 573 K and 773 K. On one hand, more dislocations, twins and strain-induced w phases are activated during the rolling at cryogenic temperatures; on the other hand, although the recovery occur during the aging, the enhanced strength is ascribed to more isothermal w phases which precipitate during the short-time aging at lower than 673K.