Microstructure Evolution of near α Titanium Alloy during Multi-Step Thermomechanical Deformation Process

Abstract:

A new type of near α high temperature titanium alloy of Ti-Al-Sn-Zr-Mo-Si-Er was studied. The samples with different primary α phase content were prepared by solid solution at 950 °C/1 h—1010 °C/1 h. The multi-step hot compression experiments were carried out by Gleeble-3500 in a sequence of upper region of α + β phase, then followed by lower region of α + β phase. The effects of primary α phase content and deformation temperature on the microstructure of the alloy were studied by means of true stress-strain curve and optical microscope. The results show that the content of primary α phase gradually decreases from 45.4% at 950°C to 0% at 1010°C. As the deformation temperature decreases from 940°C to 900°C, the content of α phase increases gradually from 65% to 94%, which is changed from dynamic recrystallization to deformed structure elongated along RD direction. It is found that the arrangement of α phase along RD direction is the longest at 920°C. With the increase of the deformation temperature in the multi-step high temperature region from 970°C to 990°C, the width of deformed α phase decreases from 3.64 μm at 970°C to 2.71 μm at 990°C. The optimized microstructure is composed of 20% primary α phase arranged along RD direction. This process has a certain potential in the process of hot deformation of the alloy. Key words: high temperature titanium alloy, primary α phase, multi-step hot deformation

• Periodical: Materials Science Forum (Volume 1035)
• Pages: 305-311
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1035.305
• Online since: June 2021
• Authors: Qing Shan Liu, Bo Long Li*, Tong Bo Wang, Cong Cong Wang, Peng Qi, Zuo-Ren Nie
• Keywords: High Temperature Titanium Alloy, Multi-Step Hot Deformation, Primary α Phase

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