ECAP对SLM纯钛组织及其耐腐蚀性能的影响

Effect of ECAP on Microstructure and Corrosion Resistance Properties of SLM Pure Titanium

为了提高纯钛在林格氏模拟体液和模拟口腔唾液环境中的耐腐蚀性能,采用等通道转角挤压(ECAP)技术对激光选区熔化(SLM)技术制备的商业纯钛进行改性处理。通过透射电子显微镜和电子背向散射衍射技术对SLM纯钛和SLM+ECAP纯钛进行组织检测,并在三电极体系下进行耐腐蚀性能的测试。结果表明:SLM+ECAP纯钛比SLM纯钛试样的晶粒尺寸小,晶界多,位错密度增大,极图的择优取向不太明显,但极密度有所增加。在林格氏模拟体液和模拟口腔唾液环境中,SLM+ECAP纯钛比SLM纯钛的自腐蚀电流密度小,极化电阻大,阻抗半径大。采用ZSimp Win软件对交流阻抗谱进行等效电路拟合,拟合结果和实验测量数据较为吻合。SLM+ECAP纯钛的耐腐蚀性能比SLM纯钛好。

In order to improve the corrosion resistance of pure titanium in Ringer ’ s simulated body fluid and simulated oral saliva environment, the equal channel angular pressing(ECAP) technique was used to modify the commercial pure titanium prepared by selective laser melting(SLM). The microstructures of SLM pure titanium and SLM+ECAP pure titanium were detected by transmission electron microscope and electron back-scattered diffractometer, and their corrosion resistance was tested by the threeelectrode system. Results show that compared with SLM pure titanium, SLM+ECAP pure titanium has smaller grain size, more grain boundaries, higher dislocation density, and modest preferred orientation of the pole diagram with increased pole density. In Ringer’s simulated body fluid and simulated oral saliva environment, SLM+ECAP pure titanium has lower self-corrosion current density,higher polarization resistance, and larger impedance radius than SLM pure titanium does. The equivalent circuit fitting of alternating current impedance spectrum was conducted by ZSimp Win software, and the fitting results are in good agreement with the experiment data. The corrosion resistance of SLM+ECAP pure titanium is better than that of SLM pure titanium.