去应力退火对LPBF TC4合金在1%NaCl溶液中的腐蚀行为影响

On the influence of stress relief annealing on the corrosion behaviors of LPBF TC4 alloys in 1%NaCl solution

本文利用电化学阻抗谱和动电位极化曲线研究了去应力退火对激光粉末床熔融(LPBF)技术制备的TC4钛合金在1%NaCl溶液中的电化学行为,并采用Mott-Schottky测试、X射线光电子能谱仪对其表面钝化膜进行了分析。结果表明:LPBF TC4合金由针状α'/α马氏体组成,而800℃去应力退火后的组织为α+β双相结构;去应力退火导致LPBF TC4钛合金的耐蚀性降低,极化电阻降低,腐蚀电流密度和钝化电流密度增加。退火处理前后LPBF TC4钛合金的钝化膜均为n-型半导体,但去应力退火后合金的载流子密度增加,且钝化膜中TiO2的含量降低,导致合金的耐腐蚀性能降低。

The electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization curves(PDP)are utilized to investigate the effect of stress relief annealing on electrochemical behavior of TC4 titanium alloy fabricated using Laser Powder Bed Fusion(LPBF)in 1%NaCl solution.Additionally,Mott-Schottky test and X-ray photoelectron spectroscopy(XPS)are employed to analyze the properties of the passive films formed on the surface of the alloys.The results indicate that the LPBF TC4 titanium alloy is primarily composed of acicularα'martensite,whereas possessesα+βdual-phase structure after stress relief annealing.Stress relief annealing deteriorates the corrosion resistance of LPBF TC4 alloy,resulting in the lower polarization resistance and higher corrosion current density.The passive films on both alloys LPBF TC4 titanium alloy exhibit n-type semiconductors with and without stress relief annealing,but the carrier density of the alloy increases after the stress relief annealing and the fraction of TiO2 in the passive film decreases,leading to a decrease in the deterioration in corrosion resistance.