长期时效对EMS206合金组织与性能的影响%Effect of long-term aging on microstructure and properties of EMS206 alloy
江苏科技大学材料科学与工程学院,江苏镇江 212100 江苏申源集团有限公司,江苏泰州 225722 盐城工学院机械工程学院,江苏盐城 224051 河南省科学院材料研究所,河南郑州 450053
2025-10-13
EMS206合金 时效 σ相 力学性能 析出相
EMS206合金经1160 ℃固溶30 min和750 ℃时效4 h的热处理后置于750 ℃进行50~4000 h长期时效,用金相显微镜观察了组织,用拉伸试验机测试了力学性能,在扫描电镜下观察了断口形貌,用TEM分析了合金中相组成.结果表明,随时效时间的延长,合金晶粒尺寸未发生明显长大,组织中M23C6相和MX相的含量增加.时效100 h后,晶界处M23C6相在晶粒内部呈颗粒状析出,时效400 h后,晶内析出物MX相增多,时效1600 h后,颗粒状MX相尺寸逐渐增大,时效2400 h后,基体中逐渐出现σ-FeCr相.随时效时间的增加,EMS206合金的硬度呈下降趋势,由332.2 HV下降至296.4 HV,断后伸长率由22.8%下降至8.8%.%EMS206 alloy was heat-treated at 1160 ℃ ×30 min+750 ℃ ×4 h and then subjected to long-term aging at 750 ℃ for 50-4000 h,the microstructure was observed by means of metallographic microscope,the mechanical properties were tested by tensile testing machine,the fracture morphology was observed under scanning electron microscopy,and the intermediate phase composition of the alloy was analyzed by means of TEM.The results show that with the extension of the aging time,the grain size of the alloy does not increase significantly,and the relative contents of Mn C6 and MX phases in the microstructure increase.After aging for 100 h,the M23C6 phase at grain boundary precipitates in the form of particles inside the grains,after aging for 400 h,the MX phase of intragranular precipitates increases,after aging for 1600 h,the size of the granular MX phase gradually increases,and after aging for 2400 h,the σ-FeCr phase gradually appears in the matrix.With the increase of aging time,the hardness of the EMS206 alloy decreases from 332.2 HV to 296.4 HV,and the elongation decreases from 22.8%to 8.8%.
