激光焊和脉冲氩焊对钛耐腐蚀性的影响

目的：探讨激光焊和脉冲氩孤焊对耐腐蚀性的影响。方法：采用动电位极化技术,分别测定激光焊接及脉冲氩孤焊接TA2和TC4后,材料阳极极化曲线的变化。将焊接后的拉伸试样浸入37℃人工唾液中,90d取出,利用原子吸收能谱和化学分析方法测定人工唾液中的钛离子浓度,同时用万能拉伸实验机测试浸泡后材料的拉伸负荷及屈服负荷。结果：自腐蚀电位的顺序为：激光焊TA2＞激光焊TC4＞脉冲氩孤焊TA2＞脉冲氩弧焊TC4＞TA2＞TC4,极化电阻的顺序为：TA2（激光焊TC4）＞TC4＞激光焊TA2（脉冲氩弧焊TA2）＞脉冲氩弧焊TC4。未焊接的TA2和TC4均测到点蚀电位,激光焊接TC4、脉冲氩（脉冲氩弧焊TA2）＞脉冲氩弧焊TC4。未焊接的TA2和TC4均测到点蚀电位,激光焊接TC4、脉冲氩弧焊接TA2及TC4的极化曲线未测到点蚀电位。激光焊接TA2点蚀电位较高,钝化电流较小。测得的Ti离子浓度均小于0．398μg/cm^2,浸蚀前后材料的拉伸负荷、屈服负荷无明显变化。结论：激光焊和脉冲氩焊焊接后材料在人工唾液中的耐腐蚀性有所增强,激光焊接后耐腐蚀性增加较明显。

The effect of laser welding or pulsed tungsten argon arc welding on the corrosion resistance of titanium

Objective: To investigate the influence of laser welding or pulsed tungsten argon arc welding on the corrosion resistance of titanium.Methods: Electrochemical technique was adopted to detect the changes of anode polarization curves of TA2 and TC4 after welding with laser or pulsed tungsten argon arc. Tensile specimens of untouched and welded TA2 and TC4 were immersed in artificial saliva at 37℃ for 90 days. The amount of Ti released was determined by atomic absorption spectroscopy and chemical analysis. Tensile loads and yield loads were examined before and after immersion using an Instron universal testing machine. The results were analyzed by ANOVA and Student's-test.Results: The order of Ecorr potential was laser-welded TA2>laser-welded TC4>pulsed tungsten argon arc welded TA2>pulsed tungsten argon arc welded TC4>TA2>TC4. The order of polarized electric resistance was TA2=laster-welded TC4>TC4>laster-welded TA2=pulsed tungsten argon arc welded TA2>pulsed tungsten argon arc welded TC4. Pitting corrosion was found on untouched TA2 and TC4, but no on treated. The voltage of laser-welded TA2 was very high. The concentrationof Ti released from all the samples in to the artificial saliva was below 0.398g/cm2. The trensile and yield loads of all specimens were not affected by immersion in artificial saliva. Conclusion: Both welding methods may enhance corrosion resistance of TA2 and TC4 and laser welding might be more benificial.