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对P92钢进行650℃,0~5000h时效实验,采用萃取复型和电化学萃取2种方法分离时效样品中的沉淀相,采用电感耦合等离子体发射光谱仪和EDS测定萃取物中合金元素的含量,揭示Laves相析出引起的合金元素再分布规律.利用Brinell硬度计测试P92钢时效过程中的硬度变化.根据合金元素再分布特性,建立基体溶质原子贫化损伤演化方程,采用基于物理本质的CDM模型评价其析出对P92钢蠕变寿命的影响.结果表明,时效前P92钢中约86%的W和Mo固溶于基体,剩余的14%分配在M23C6中.P92钢时效过程中由于Laves相析出发生合金元素的迁移,其析出主要夺取基体中的W和Mo原子,对时效前已析出的M23C6和MX相的成分影响很小.Laves相完全析出后,基体中W和Mo的分配量均降至50%左右.Laves相的析出还消耗基体的一部分Cr,使其分配量减少约3.6%.Laves相析出明显削弱溶质原子的固溶硬化作用,CDM计算表明,其析出使P92钢在650℃,100MPa下的蠕变寿命缩短24%左右.
P92 steel was subjected to aging at 650 ℃ for 0-5000 h. The precipitated phases were separated by extraction complexation and electrochemical extraction. The content of alloying elements in the extract was determined by inductively coupled plasma atomic emission spectrometry and EDS. Revealing the rules of alloying element redistribution caused by Laves phase precipitation.The hardness change of P92 steel during aging was tested by Brinell hardness tester.According to the alloying element redistribution characteristics, The effect of precipitation on the creep life of P92 steel was evaluated.The results show that about 86% of W and Mo in P92 steels dissolve in the matrix and the remaining 14% distribute in M23C6.The aging of P92 steel is due to the precipitation of Laves phase Alloying element migration occurs, the precipitation of the main matrix to seize the W and Mo atoms, the precipitation of M23C6 and MX phase before aging has little effect on the composition of the Laves phase is completely precipitated, the matrix W and Mo distribution decreased To about 50% .The precipitation of Laves phase also consumes a part of the matrix Cr, to reduce the distribution of about 3.6% .The Laves phase precipitation significantly weaken the solid solution hardening effect of solute atoms, CDM calculations show that the precipitation P92 steel at 650 ℃, 100MPa creep life shortened by about 24%.