拉伸温度对Cr18Ni10Ti不锈钢力学性能影响  

Effect of tensile temperature on mechanical properties of Cr18Ni10Ti stainless steel

作　　者：黄昌虎 宋新莉[1] 贾涓[1] 范丽霞[1] HUANG Chang-hu;SONG Xin-li;JIA Juan;FAN Li-xia(The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]武汉科技大学耐火材料与冶金国家重点试验室,湖北武汉430081

出　　处：《材料热处理学报》2021年第9期112-118,共7页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51871064)。

摘　　要：首先对Cr18Ni10Ti不锈钢进行1050℃固溶处理及650℃时效24 h处理,随后在不同温度(500~800℃)下以1.43×10^(-4)s^(-1)拉伸速率对其进行高温拉伸试验。采用扫描电镜与能谱仪分析了试验钢的组织、析出相及断口形貌,采用高分辨透射电镜观察其位错和晶界处的P和S元素的浓度。结果表明:Cr18Ni10Ti不锈钢的组织主要是奥氏体组织,基体中有富Cr析出相及AlMgTiO复合析出相。当拉伸温度从500℃升高到800℃时,试验钢的屈服强度、抗拉强度均减小,断面收缩率先减小后增大,在650℃拉伸时,断面收缩率最小。当拉伸温度较低时,试验钢出现明显的颈缩现象,随拉伸温度升高,拉伸过程中的颈缩现象不明显,出现韧窝与沿晶混合断口。当拉伸温度升高到800℃时,试验钢发生蠕变断裂,出现冰糖状断口。第二相、拉伸过程的回复与再结晶、P和S元素的晶界偏聚行为以及晶界蠕变等多种因素的影响使得Cr18Ni10Ti不锈钢在500~800℃拉伸时出现不同的强度与断面收缩率。First,Cr18Ni10Ti stainless steel was treated by 1050℃solution treatment and aging treatment at 650℃for 24 h,and then high temperature tensile tests of the steel were carried out at 500-800℃with strain rate of 1.43×10^(-4) s^(-1).Microstructure,precipitated phase and fracture surface morphology of the experimental steel were analyzed by means of scanning electron microscopy and energy dispersive spectrometer analysis,and the dislocation and the concentration of P and S elements at grain boundary were observed by high resolution transmission electron microscopy.The results show that the microstructure of the Cr18Ni10Ti stainless steel is mainly austenite,and the Cr rich precipitates and AlMgTiO compound precipitates are found in the matrix.With the increase of tensile temperature(500-800℃),the yield strength and tensile strength of the experimental steel decrease,and the reduction of area decreases first and then increases.When the tensile temperature is 650℃,the reduction of area is the lowest.When the tensile temperature is low,the necking phenomenon of the experimental steel is obvious,and becomes less obvious with the increase of the tensile temperature,and the dimple and intergranular mixed fracture occurs.When the tensile temperature increases to 800℃,the creep fracture of the experimental steel occurs and the rock sugar-like fracture is produced.The second phase,the recovery and recrystallization during the tensile process,the grain boundary segregation behavior of P and S elements and the grain boundary creep lead to different strength and reduction of area of the Cr18Ni10Ti stainless steel at tensile temperature of 500-800℃.

关 键 词：不锈钢 拉伸温度 断口形貌 位错 晶界偏聚 

分 类 号：TG142.7[一般工业技术—材料科学与工程]