钛合金TC4塑性变形后在3%NaCl溶液中的交流阻抗谱

通过对不同应变状态下钛合金TC4在3%NaCl溶液中的交流阻抗谱的研究,发现在高应变条件下钛合金的腐蚀速度更易受到外加交流信号频率的影响.根据阳极溶解的应力腐蚀机理,腐蚀裂纹处实际上处于交流信号的扰动中,因此腐蚀裂纹处的电化学过程应与交流信号的频率有关,频率越高腐蚀速度越快,理论估计在50 Hz的频率下腐蚀速度可增加10倍以上.因此认为应力腐蚀过程中裂纹的萌生和发展与界面上产生的交流信号密切相关.

Electrochemical Impedance of Titanium Alloy TC4 with Axial Tension in 3% NaCl Solution

After comparing the electrochemical impedance of titanium alloy TC4 with different tension strains, it is considered that the corrosion rate of TC4 with high strain would be more easily affected by the frequency of corrosive current than that without strain. According to traditional stress corrosion mechanism, the stress corrosion crack was in a state of open and close alternately, and from this it made AC current. So the crack propagation would be affected by the frequency of the AC current, and when the frequency was 50 Hz, the corrosion rate was estimated to increase at least 10 times. It is concluded that in stress corrosion process the rate of crack initiation and propagation would be determined by the frequency of AC current on metal/solution interface.