摘要
本文研究了含微量硼元素的18Ni(2400MPa 级)马氏体时效钢,在低温固溶化后缓冷时引起的脆化现象。研究表明,该合金在低温固溶化缓冷过程中,产生 B 元素的晶界偏聚和 Ni、Ti 合金元素的晶界偏聚,其结果,离晶界80～100(?)处形成 Ni、Ti 元素的"贫化区",时效后这个区成为"少析出区",再加上晶界处 Ni_3Ti 金属间化合物的偏析,引起晶界脆化和晶界附近"少析出区"的弱化,使合金的韧性显著下降。
The slow cooling embrittlement of 18Ni maraging steel(2400 MP agrade)containing trace boron after solution treatment at low temperature wasstudied.The results show that the segragation of B,Ni and Ti at grain boun-daries during slow cooling after solution treatment at low temperature formsthe depleted zone of Ni and Ti which is 80～100(?) from the grain boundary.After aging,the depleted zone becomes the precipitate-free zone.Besides,thesegragation of Ni_3Ti metallic compounds at grain boundaries leads to the grainboundary embrittlement and the weakness of the precipitate-free zone,resultinginthe descent of impact toughness.
关键词
马氏体时效钢
硼
固溶热处理
脆化
maraging steel
boron
solution heat treatment
slow cooling
embrittlement
