中文摘要：

利用冲击试验、扫描电镜和透射电镜观察研究了不同稀土Ce含量对00Cr17钢冲击韧性及475℃脆性的影响。结果表明,随着钢中Ce含量的增加,00Cr17钢的横向和纵向冲击韧性均先增加后减少,在含0.02%Ce时最大。冲击韧性的改善是由于稀土Ce的加入改变了钢中非金属夹杂的形貌和类型。随着475℃时效时间的增加,不同Ce含量的00Cr17钢的冲击韧性均逐渐减小,并最终趋于零,呈现完全脆性断裂。但在475℃时效时间小于196h时,含Ce钢的冲击韧性高于不含Ce的钢,即减缓00Cr17钢的475℃脆化速度,这是由于稀土Ce的加入抑制了钢中α′相的析出。

英文摘要：

Effects of Ce on impact toughness and 475 ℃ embrittlement of high purity 00Cr17 ferrite stainless steel were investigated by impact test,scanning electron microscopy（SEM）and transmission electron microscopy（TEM）.The results show that both the cross direction and longitudinal direction impact toughness of 00Cr17 steel increases first and then decreases with the increasing of Ce,and the maximum value of toughness is obtained at 0.02% Ce.The improvement of impact toughness is ascribed to the change of morphology and types of nonmetallic inclusions due to the Ce addition.As the aging time increasing,the impact toughness of 00Cr17 steels with different Ce contents decreases gradually and tends to zero,and the completely brittle fracture occurs eventually.But for the steels aged at 475 ℃ for time less than 196 h,the impact toughness of steel with Ce addition is higher than that of steel without Ce addition.It is found that the 475 ℃ embrittlement of 00Cr17 steel is retarded due to the Ce addition,which results from that precipitation of α＇ phase is restrained by Ce addition.