Laves相析出对P92钢合金元素再分布的影响  

EFFECT OF LAVES PHASE PRECIPITATION ON REDISTRIBUTION OF ALLOYING ELEMENTS IN P92 STEEL

作　　者：王学[1,2] 李勇[1] 任遥遥[1] 刘洪伟 刘洪 王伟[4] 

机构地区：[1]武汉大学动力与机械学院,武汉430072 [2]武汉大学流体机械与动力工程装备技术湖北省重点实验室,武汉430072 [3]东方电气集团东方锅炉股份有限公司,自贡643001 [4]广东电网公司电力科学研究院,广州510080

出　　处：《金属学报》2014年第10期1203-1209,共7页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目51074113和51374153;四川省应用基础研究计划项目2013JY0123资助~~

摘　　要：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.The P92 steel specimens were aged at 650 ℃ for 0~5000 h,and precipitates of the aged specimens were extracted from the matrix using carbon extraction replicas and potentiostatic electrolysis.The amount of alloy elements in extracted precipitates was determinded by inductively coupled plasma-atomic emission spectrometry（ICP-AES） and EDS,then the redistribution of alloying elements owing to Laves phase formation was analyzed.The hardness of aged specimens was taken using a Brinell hardness tester.The damage evolution equation owing to solute depletion was obtained from the redistribution characteristic of alloying elements and its influence on the creep life of P92 steel was evaluated based on the physical CDM model.The results are as follows.Before aging,about 86% contents of W and Mo in P92 steel are supersaturated in matrix and the remains are in M23C6 carbides.The removing of alloy elements take place due to the precipitation of Laves phase during aging.The formation of Laves phase consumes mainly W and Mo in matrix,and has little effect on the compositions of M23C6 cabides and MX carbonitrides precipitated before aging.The partition coefficients of these two elements supersaturated in matrix reduce up to 50% on the completion of Laves phase precipitation,and the Cr content in the matrix decreases about 3.6% because the formation of the Laves phase consumes Cr.The precipitation of Laves-phase contributes to the significant decreasing of solution hardening,causes the creep life of P92 steel reduction of about24% at 650 ℃,100 MPa.

关 键 词：P92钢 LAVES相 合金元素 再分布 

分 类 号：TG142.7[一般工业技术—材料科学与工程]