锰对结构钢中磷在晶界偏聚的影响

INFLUENCE OF Mn ON AGGREGATION OF P AT GRAIN-BOUNDARY IN STRUCTURAL STEELS

作者通过 IMA—Ⅱ型离子探针和萃取分析等实验方法,研究了锰对磷在晶界上偏聚量的影响。结果表明,锰和磷的共偏聚作用控制着磷的晶界偏聚量,而基体中锰的固溶量又控制着这种共偏聚作用,从而控制着含锰结构钢韧脆转变温度的高低。脆化初期,锰和磷向晶界的偏聚作用强,使韧脆转变温度升高。随着回火脆化时间增加,锰和磷向晶界的偏聚趋于平衡,与此同时,锰不断溶入渗碳体,使磷发生共偏聚的基体固溶锰量降低,又使磷从晶界上解聚,导致韧脆转变温度降低。

By means of Ion Probe IMA-Ⅱ and by extractive analysis,the influence of Mn on aggregation of P at grainboundary is studied.The finding show that the partial aggregated amount of P at the grain-boundary is controled by the partial co-aggregation of Mn and P while this partial co-aggrega- tion is again,controled by the amount of Mn in sosoloid in matrix.The transtional temperature of an Mncontaining structural steel upon its tran- sition from toughness to brittleness depends on the concentrartion of Mnin sosoloid in the steel matrix.In the earlier phase embritllement,Mn and P tend to co-aggregate partially at the grain-boundary and the transition temperature tends to be high.with the time of temperiag embrittlement going on,such a co-aggregation at the grain-boundary arrives at equili- brium while the steady dissolution of Mn into cementite makes the Mn in sosoloid in the matrix gradually decrease.The latter dissolution causes P to separate from the grain-boundary and lowers the toughness-to-brittleness transitional temperature.