采用失重法、SEM及SSRT等手段研究了不同热处理温度对G3合金局部腐蚀行为的影响。结果表明,G3合金具有优异的抗点蚀性能,而析出相的生成和溶解是影响G3合金点蚀敏感性的主要因素,大量析出相会使合金表面钝化膜的均匀性遭到较大的破坏。随着热处理温度的升高,大量析出相的生成使G3合金钝化膜保护性变差,耐缝隙腐蚀性能变低;在700℃热处理时最低,900℃热处理时由于再结晶现象的发生使得析出相在局部区域富集,G3合金耐缝隙腐蚀性能有所提高。G3合金经700℃保温2h空冷后,断口形貌由韧性断裂向脆性断裂转变,材料的应力腐蚀开裂敏感性明显增强。

The effect of thermal treatment temperature on localized corrosion of G3corrosion resistant alloy(CRA)was studied by SEM,SSRT and weight loss methods.The results show that G3CRA has excellent pitting corrosionresistance.The formation and dissolution of precipitates are the major factors influencing the pitting of G3alloy,thelarge number of precipitates can make considerable damage to the uniformity of the passive film,the susceptibility topitting increases.With the increase of thermal treated temperature,the formation of large amounts of precipitatesdeteriorates the protection of the passive film,and the crevice corrosion resistance becomes low.The crevice corrosionresistance was the lowest after annealing at 700 ℃ for 2h.When the allay was annealed at 900 ℃ for 2h,theprecipitates were enriched at local area as a result of re-crystallization and the crevice corrosion resistance of G3CRAwas improved.The fractures of G3CRA changed from ductile fracture to brittle fracture after annealing at 700℃for2h,and the susceptibility to stress corrosion cracking was significant increased.