14Cr-ODS钢的热时效行为

为探究氧化物弥散强化(Oxide dispersion strengthened, ODS)钢的热稳定性,采用机械合金化和热等静压烧结的方法制备成分为Fe-14Cr-2W-0.3Ti-0.2V-0.07Ta-0.3Y₂O₃ (wt%)的14Cr-ODS钢,在700 ℃分别对其进1000、2000和3000 h时效处理,表征了ODS钢组织及第二相在热时效过程中的变化规律,同时分析了ODS钢的维氏硬度值。结果表明:M₂₃C₆相在时效过程中逐渐溶解,促进了TiC相和Y₂Ti₂O₇相的析出。烧结态ODS钢中球状的Y₂Ti₂O₇相在长时间的时效过程中逐渐转变为立方状,且Y₂Ti₂O₇相的尺寸在时效过程中未发生变化。当时效时间延长至2000 h和3000 h时,ODS钢的基体组织及第二相保持稳定,硬度结果也与该现象相对应。

Thermal aging behavior of 14Cr-ODS steel

In order to investigate the thermal stability of oxide dispersion strengthened (ODS) steel, 14Cr-ODS steel with Fe-14Cr-2W-0.3Ti-0.2V-0.07Ta-0.3Y₂O₃ (wt%) was prepared by means of mechanical alloying and hot isostatic pressing (HIP) sintering, and the long time thermal aging was carried out at 700 ℃ for 1000 h, 2000 h and 3000 h, respectively. The evolution of microstructure and secondary phases during the thermal aging was characterized. In addition, the Vickers microhardness values of the ODS samples were analyzed. The results indicate that no obvious change of microstructure can be found during the thermal aging process. The M₂₃C₆ particles partially dissolve into the matrix, thus promoting the precipitation of TiC and Y₂Ti₂O₇ nanoparticles during aging. The spherical Y₂Ti₂O₇ particles in the as-sintered ODS specimen turn into cuboidal without changing of size after long time aging. Both the matrix microstructure and secondary phases keep stable when the aging time increases to 2000 h and 3000 h, to which the microhardness results correspond.