Heat Treatment of Metals ›› 2022, Vol. 47 ›› Issue (9): 41-46.DOI: 10.13251/j.issn.0254-6051.2022.09.008

• PROCESS RESEARCH • Previous Articles     Next Articles

Effect of annealing process on microstructure and corrosion resistance of Ti-4Al-2V alloy

Wang Lu, Wang Feng, Zhang Mingwei, Liu Rui, Fu Zhengyuan, Liu Jingshun   

  1. School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot Inner Mongolia 010051, China
  • Received:2022-04-18 Revised:2022-07-13 Published:2022-10-18

Abstract: Extruded bars of Ti-4Al-2V alloy were treated by ordinary annealing, recrystallization annealing and double annealing, and the microstructure before and after heat treatment was characterized by X-ray diffractometer and scanning electron microscope. Meanwhile, the corrosion resistance of the titanium alloy in 3.5%NaCl solution was tested by electrochemical workstation, and the correlation between the heat treatment process and the corrosion tendency of the alloy was analyzed. The results show that there is no obvious macro and micro defect on the surface of the untreated alloy rod, and the microstructure of the titanium alloy is mainly α phase annealed at different temperatures. After double annealing at 960 ℃+570 ℃, the alloy is composed of coarse-grained α phase and fine needle-like α phase. The untreated alloy is accompanied with a basketweave microstructure, and a small amount of Widmannstatten structure and two-state structure are obtained after different heat treatment. By analyzing the polarization curves and electrochemical impedance spectroscopy of titanium alloy annealed at different temperatures, it can be seen that compared with the untreated alloy, the self-corrosion current density of the alloy annealed at 760 ℃ is smaller, the corresponding polarization resistance is larger, and the corrosion tendency is smaller. The Nyquist plot of the alloy after double annealing at 960 ℃+570 ℃ shows the largest capacitive arc resistance, indicating better corrosion resistance.

Key words: annealing process, Ti-4Al-2V alloy, microstructure, corrosion resistance, polarization curve

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