中文摘要：

对加稀土前后09Cr2A1MoRE钢取样分析化学成分，制备金相样用SEM-EDS研究了钢中析出物特征，制备透射电镜（TEN）试样通过TEM研究元素的晶界偏聚，并用热力学计算了稀土Ce，La，S和残余元素As反应固定残余元素As的可能性。研究结果表明：在低氧、硫的条件下，稀土镧可以和09Cr2AIMoRE钢中较低含量的砷（130×10^-6）作用生成镧砷金属间化合物；铈、镧主要是通过形成稀土砷硫夹杂物固定钢中残余元素砷。另外，在本实验条件下稀土元素（64×10-6）只有很微量的偏聚在晶界，残余元素As不在晶界偏聚。

英文摘要：

The chemical compositions for the 09Cr2A1MoRE steel before and after adding rare earth were analyzed. The characteristics of inclusions were observed by SEM-EDS after prepared the metallo- graphic specimens and the segregation of the elements at the grain boundary was studied by transmission e- lectron microscopy （TEM）. And the possibility of the reactions of rare earth Ce, La, S and residual element As to improve the harm influence of the residual ele- ments As on the steel properties were calculated by u- sing thermodynamic analysis. The results showed that lanthanum can react with low content of arsenic （ 130 ppm ） to form role lanthanum-arsenic intermetallic compound, and the arsenic was mainly fixed by the reaction with cerium, lanthanum and sulfur. In addi- tion, under the present experimental conditions, rare earth elements （64 ppm） were only a trace of partial segregated in grain boundary, and residual element ar- senic （130 ppm） was not in ry. Above all, in the low tions, the mechanism of rare segregated grain bounda- oxygen and sulfur condi- earth improving the harm influence of the residual elements As on 09Cr2AlMoRE steel are mainly that the fixation of RE and S on residual elements As is effectively reducing the solution quantity of residual elements As in ma- trix, which results in the segregation eliminating of re- sidual elements As at the grain boundary