选用合理的机械合金化工艺,可使合金粉中的弥散相Y2O3在机械合金化及随后的热固化过程中分解,井生成更加细小和稳定的复合氧化物Y2Ti2O7,提高合金的蠕变强度.当合金中Ti含量大于2.0%时,合金经800℃,24h时效(650℃长期服役),将有X相析出,导致合金的蠕变强度明显降低.
When an optimum machanical alloying(MA) process was selected, the dispersoids (Y2O3) added in the ferritic alloy will initially dissolve into a matrix during MA, then a kind of super fine complex oxide(Y2Ti2O7) will precipitate during following hot consolidation process By this transition, the dispersoids can be obviously refined from 30 um (Y2O3) to smaller than 10 nm (Y2Ti2O7) and even more uniformly distributed in alloy matrix. It can remarkably enhance the effect of dispersion strengthening and enable the alloy's strength, especially creep strength,to reach a superior high level enough to satisfy the specification of commercial type FBR. But when a high content of Ti (>2%) is added in the alloy, X phase can easily precipitate in the alloy's matrix during aging the alloy at 800℃ for 24 h, which can not contribute to 650℃ tensile strength, and is very harmful to tensile ductility and creep strength of the alloy.
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