Effects Of Preparation Technology And Silicon On Microstructure And Properties Of14Cr-ODS Ferritic Steel

Nano-metric oxide dispersion strengthened (ODS) ferrite steels used in fusion reactorproduced by mechanical alloying techniques have become increasingly interesting toscientific researchers. This article briefly introduced fusion reactor and the currentsituation of its structural materials, and then summarize the processing of ODS steels.Based on the theories of above, Fe-14Cr-2.5W-0.4Ti-0.3Y2O3-xSi (wt%) nominal compos-ition powders were produced by MA, then the superalloy powders were treated byannealing, compacting, sintering and14-ODS ferritic steel were achieved. By means ofrelative density test, mechanical properties test, hardness test, oxidation test and a series ofanalysis methods(XRD, OM, SEM+EDS), the effects of MA parameters, sinteringtemperature and the content of silicon on microstructure and properties at roomtemperature of the14Cr-ODS ferritic steel were studied. The14Cr-ODS ferritic steels’oxidation behavior were also studied. Main conclusions as follows:1. Raw powders could be basically realized alloying after48h ball milling，undercondition of230r/min，20:1(BPR). The composition of superalloy powders wereclose to the composition designed. Add1wt%SA into the MA powders and then ballmilling for4h could make powders more mellow. The SA added to the powdersplayed a role of self-lubricating, which could improve the property of powders in theuppression process.2. The relative density of14Cr-ODS steel could be apparently improved by addition ofsilicon, the alloy with5wt%Si sintered at1380°C were up to93.7%.3. The microstructure of14Cr-ODS alloy sintered at1300°C is uniform，the grains sizewere fine and equiaxed. The mechanical property of the steel were good，the tensilestrength，elongation and hardness of the alloy were respectively468.54Mpa,25.21%and178.3HV. The mechanical property could obviously enhanced by addition of Si, the tensile strength， elongation and hardness of the alloy were respectively653.36Mpa,28.56%and276.8HV.4. The oxide layer of alloys with silicon addition were more compacted and flat，thisindicates that adding silicon into the alloy can significantly improve the anti-oxidantproperties of the alloy.