轧制变形对690合金特殊晶界比例及耐晶间腐蚀性能的影响

EFFECTS OF ROLLING ON THE SPECIAL GRAIN BOUNDARIES AND INTERGRANULAR CORROSION OF ALLOY 690

不同轧制变形量的镍基690合金试样在1120℃×5 min的固溶处理和720℃×10 h的脱敏处理后,进行了晶粒度、特殊晶界比例及晶问腐蚀性能研究。结果表明,晶粒度随着轧制变形量的增加而升高,晶粒尺寸减小;特殊晶界比例在5%变形量试样达到最高.为67.7%,并随着轧制变形量的增加而减小,67%冷轧时特殊晶界比例降低到25.4%;ASTM G28-A法晶问腐蚀减重5%变形量的试样达到最低。

Alloy 690 specimens were deformed by rolling and followed by solution treatment at 1120 ℃ for 5 min and thermal treatment at 720 ℃ for 10 h. Grain size, special grain boundary concentration and resistance to intergranular corrosion were evaluated. The results show that the grain size number increases with the increase of deformation, concentration of special boundaries reaches the maximum of 67.7% for specimens with 5% plastic deformation, and decrease with the increase of deformation, and the concentration of special boundaries of specimens with 67% deformation decreases to 25.4%. Intergranular corrosion was evaluated using ASTM G28-A method, and specimens with 5% deformation show the lowest weight loss rate.