工程科学学报，第37卷，第5期：600607,2015年5月 Chinese Journal of Engineering,Vol.37,No.5:600-607,May 2015 DOI:10.13374/j.issn2095-9389.2015.05.010:http://journals.ustb.edu.cn 改进310奥氏体不锈钢长期时效后的组织与性能 孙红英，周张健四，王曼，邹 雷，李少夫 北京科技大学材料科学与工程学院，北京100083 ☒通信作者，E-mail:zhouzhj@mater..ustb.edu.cn 摘要借助扫描电子显微镜、透射电子显微镜以及高温、室温拉伸和硬度测试研究了实验室研发的改进310奥氏体不锈钢 在700℃长期时效后的组织与性能.700℃时效1000h后，实验钢在晶界和晶内析出了大量(Cr,Fe,Mo)sC6、(Cr,Fe)3C6o 相和少量的X相.析出相对实验钢的室温力学性能有明显的强化作用.强度增加，硬度升高20H,同时延伸率仍保持在 30%以上.高温下，析出强化效应减弱，延伸率轻微下降.通过断口表面和剖面观察发现，时效1000h后，实验钢的高温拉伸 断口为韧性断裂，未观察到裂纹和孔洞：而室温拉伸断口为脆性断裂，断口附近则观察到σ相中出现裂纹和孔洞.从σ相的 脆一韧转变和实验钢基体的室温和高温强度的不同，讨论了在室温拉伸过程中产生裂纹和孔洞的原因，以及时效对室温和高 温力学行为的不同影响. 关键词奥氏体不锈钢：时效：析出相：显微组织：力学性能 分类号TG142.71 Microstructures and mechanical properties of a new 310 austenitic stainless steel during long term aging SUN Hong-ying,ZHOU Zhang jian,WANG Man,ZOU Lei,LI Shaofu School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China Corresponding author,E-mail:zhouzhj@mater.ustb.edu.cn ABSTRACT The microstructures and mechanical properties of a modified 310 austenitic stainless steel during isothermal aging at 700C were investigated by using scanning electron microscopy (SEM)and transmission electron microscopy (TEM),tensile testing at ambient temperature and 700C,and micro-hardness testing.It was found that massive block (Cr,Fe,Mo)2C(Cr,Fe)2C car- bides,o-phase and a small quantity of x-phase formed on grain boundaries and within grains in the tested steel after aging at 700C for 1000 h.Precipitates significantly strengthened the mechanical properties of the tested steel at room temperature.The strength increased and the hardness raised by 20 Hv,while the elongation still remained above 30%.However,at high temperature,the effect of precip- itation strengthening was weakened,and the ductility slightly decreased.Fracture surface and cross-sectional microstructural analysis after tensile testing showed that the high temperature tensile fracture mode after aging for 1000 h was ductile fracture;neither cracks nor holes were observed:but the room temperature tensile fracture was brittle,and there were some cracks and holes in o-phase near the fracture.Finally,from the ductile-brittle transition of o-phase and the difference in strength between room temperature and 700C, this article discussed the reason for crack and hole forming in the stretching process at room temperature as well as the different effects of aging on the mechanical properties at room temperature and high temperature KEY WORDS austenitic stainless steel:aging:precipitates:microstructure:mechanical properties 奥氏体不锈钢具有优良的高温力学性能和抗氧化 性能，是先进核电站、航空航天等行业高温结构部件的 收稿日期：2013-12-26 基金项目：国家重点基础研究发展计划资助项目(2007CB209800)工程科学学报，第 37 卷，第 5 期: 600--607，2015 年 5 月 Chinese Journal of Engineering，Vol． 37，No． 5: 600--607，May 2015 DOI: 10． 13374 /j． issn2095--9389． 2015． 05． 010; http: / /journals． ustb． edu． cn 改进 310 奥氏体不锈钢长期时效后的组织与性能 孙红英，周张健，王 曼，邹 雷，李少夫 北京科技大学材料科学与工程学院，北京 100083  通信作者，E-mail: zhouzhj@ mater． ustb． edu． cn 摘 要 借助扫描电子显微镜、透射电子显微镜以及高温、室温拉伸和硬度测试研究了实验室研发的改进 310 奥氏体不锈钢 在 700 ℃长期时效后的组织与性能． 700 ℃时效 1000 h 后，实验钢在晶界和晶内析出了大量( Cr，Fe，Mo) 23C6、( Cr，Fe) 23C6、σ 相和少量的 χ 相． 析出相对实验钢的室温力学性能有明显的强化作用． 强度增加，硬度升高 20 Hv，同时延伸率仍保持在 30% 以上． 高温下，析出强化效应减弱，延伸率轻微下降． 通过断口表面和剖面观察发现，时效 1000 h 后，实验钢的高温拉伸 断口为韧性断裂，未观察到裂纹和孔洞; 而室温拉伸断口为脆性断裂，断口附近则观察到 σ 相中出现裂纹和孔洞． 从 σ 相的 脆--韧转变和实验钢基体的室温和高温强度的不同，讨论了在室温拉伸过程中产生裂纹和孔洞的原因，以及时效对室温和高 温力学行为的不同影响． 关键词 奥氏体不锈钢; 时效; 析出相; 显微组织; 力学性能 分类号 TG142. 71 Microstructures and mechanical properties of a new 310 austenitic stainless steel during long term aging SUN Hong-ying，ZHOU Zhang-jian ，WANG Man，ZOU Lei，LI Shao-fu School of Materials Science and Engineering，University of Science and Technology Beijing，Beijing 100083，China  Corresponding author，E-mail: zhouzhj@ mater． ustb． edu． cn ABSTＲACT The microstructures and mechanical properties of a modified 310 austenitic stainless steel during isothermal aging at 700℃ were investigated by using scanning electron microscopy ( SEM) and transmission electron microscopy ( TEM) ，tensile testing at ambient temperature and 700℃，and micro-hardness testing． It was found that massive block ( Cr，Fe，Mo) 23C6，( Cr，Fe) 23C6 car￾bides，σ-phase and a small quantity of χ-phase formed on grain boundaries and within grains in the tested steel after aging at 700℃ for 1000 h． Precipitates significantly strengthened the mechanical properties of the tested steel at room temperature． The strength increased and the hardness raised by 20 Hv，while the elongation still remained above 30% ． However，at high temperature，the effect of precip￾itation strengthening was weakened，and the ductility slightly decreased． Fracture surface and cross-sectional microstructural analysis after tensile testing showed that the high temperature tensile fracture mode after aging for 1000 h was ductile fracture; neither cracks nor holes were observed; but the room temperature tensile fracture was brittle，and there were some cracks and holes in σ-phase near the fracture． Finally，from the ductile-brittle transition of σ-phase and the difference in strength between room temperature and 700 ℃， this article discussed the reason for crack and hole forming in the stretching process at room temperature as well as the different effects of aging on the mechanical properties at room temperature and high temperature． KEY WOＲDS austenitic stainless steel; aging; precipitates; microstructure; mechanical properties 收稿日期: 2013--12--26 基金项目: 国家重点基础研究发展计划资助项目( 2007CB209800) 奥氏体不锈钢具有优良的高温力学性能和抗氧化 性能，是先进核电站、航空航天等行业高温结构部件的