【摘要】 利用电化学方法,结合其它技术等表面分析手段,研究了深冷大载荷冲击热处理组合方法制备的TA7钛合金超细晶块体材料在3.5 wt%NaCl溶液中的腐蚀行为。研究结果表明,在3.5wt%NaCl溶液中,原材料、冲击以及冲击后热处理TA7块体材料的极化行为存在明显差异,冲击以及冲击后热处理TA7块体材料为活性溶解-钝化-过钝化,而原始粗晶TA7块体材料为活性溶解。X射线光电子能谱（XPS）分析表明,冲击后600℃热处理TA7块体材料在活性溶解区主要表现为SnO的生成,在钝化区为TiO₂和Al₂O₃氧化膜的生成,在过钝化区表现为Sn和部分Ti的溶解。冲击后TA7块体材料耐蚀性较原始粗晶TA7块体材料显著提高,归因于冲击可有效细化组织,并导致位错、空位等缺陷密度提高,有效促进钝化。冲击后进行600℃热处理,组织进一步细化,缺陷密度降低,综合作用使得耐蚀性优于原始粗晶TA7块体材料。更多还原

【Abstract】 The anodic polarization behavior of ultrafine grain TA7 titanium alloy bulks formed by cryogenic impact in 3.5 wt% NaCl was investigated using electrochemical methods and some other techniques.It was found that the impacted TA7 bulks with or without heat treatment notably differed from as-received coarse-grain TA7 bulk in their anodic polarization behavior.The former were active dissolution-passivationoverpassivation,but the latter was active dissolution.X-ray photoelectron spectroscopy（XPS）analysis revealed that the corrosion behavior of the impacted TA7 with heat treatment at 600℃consisted of three parts:（1）the formation of SnO at the active dissolution period,（2）the formation of TiO₂ and Al₂O₃ oxide film at the passivation period,（3）the dissolution of Sn and some Ti at the overpassivation period.The corrosion resistance of thimpacted TA7 bulk was significantly higher than that of as-received bulk due to the refining of structure and increase of the defect density such as dislocation as well as vacancy.After heat treatment at 600 ℃,the grain size was further refined while the defect density was reduced,resulting in the corrosion resistance was better than as-received coarse-grain TA7 bulk.更多还原