室温等径转角挤压对18Ni(C-250)马氏体时效钢微观组织和拉伸性能的影响  

EFFECT OF EQUAL-CHANNEL ANGULAR PRESSING ON THE MICROSTRUCTURES AND TENSILE PROPERTIES OF 18Ni(C-250) MARAGING STEEL

作　　者：杨沐鑫[1,2] 杨钢[2] 刘正东[2] 王昌[2] 胡超[2] 黄崇湘[3] 

机构地区：[1]昆明理工大学材料科学与工程学院,昆明650093 [2]钢铁研究总院结构材料研究所,北京100081 [3]四川大学建筑与环境学院,成都610065

出　　处：《金属学报》2012年第2期164-169,共6页Acta Metallurgica Sinica

基　　金：国家自然科学基金资助项目50971045~~

摘　　要：采用等径转角挤压(ECAP)工艺在室温下对18Ni(C-250)马氏体时效钢进行单道次冷变形.对比固溶处理试样480℃时效曲线、固溶+ECAP处理试样的460和480℃时效曲线发现,一道次ECAP变形及随后的时效处理能够使马氏体时效钢的峰值时效时间明显缩短,峰值强度提高约100 MPa.结构分析表明,ECAP态实验钢的马氏体板条宽度为100—200 nm,随后的时效过程对马氏体板条宽度影响不大,而ECAP工艺对棒状δ-Ni3Mo相析出尺寸有显著影响.统计结果表明,经4 h时效处理后.固溶+480℃时效态、固溶+ECAP+480℃,460℃时效态的δ-Ni_3Mo宽度(直径)分别为4.92,12.33和3.54 nm.此外,ECAP工艺还促使18Ni马氏体钢中δ-Ni3Mo相在时效后期加速分解,使强度迅速衰减.An 18Ni（C-250） maraging steel was successfully processed by equal-channel angular pressing（ECAP） for a single pass at room temperature.After ECAP deformation,the peak aging time was cut obviously and the peak strength of the steel was enhanced about 100 MPa.Microstruc- tural observations showed that the martensite laths of 18Ni maraging steel were elongated to more narrow bands with a width of 100—200 nm after ECAP deformation,and the width of martensite lath was not affected by the subsequent aging treatment.ECAP deformation has significant influence on the size of rod-shaped 5-Ni3Mo precipitates.It was observed that the widths（diameters） of pre- cipitates in specimens under treatments of solution＋480°C,4 h,solution＋ECAP＋480°C,4 h and solution＋ECAP＋460°C,4 h are 4.92,12.33 and 3.54 nm,respectively.Additionally,a decomposition of the 5-Ni3Mo precipitates was accelerated after the peak aging time,resulting in a decrease in the strength.

关 键 词：马氏体时效钢 等径转角挤压(ECAP) 力学性能 时效强化 

分 类 号：TG142.1[一般工业技术—材料科学与工程]