摘要
对21-4NWNbMoCu合金进行了标准热处理(1100℃×0.5 h+750℃×4 h),探究了标准热处理后合金在750℃长期时效(100~4000 h)后的组织和力学性能演变规律。结果表明:随着时效时间的延长,晶内与晶界上的第二相明显增多,由于合金中第二相粒子析出对晶界起到了钉扎作用,抑制了晶界的迁移,晶粒尺寸未发生明显长大;通过扫描电镜与透射电镜发现,NbC相和WN相的存在是合金组织稳定的主要因素。合金强度随着时效时间延长呈下降趋势,这主要受晶内弥散型碳化物的Ostwald熟化机制的影响;合金硬度的增加与M_(23)C_(6)型碳化物持续析出相关;晶界处粗大M_(23)C_(6)型碳化物导致了合金的伸长率随着时效时间的延长而下降,断口形貌表现为脆性断裂特征。
Microstructure and mechanical properties of 21-4NWNbMoCu alloy were investigated after standard heat treatment(1100℃×0.5 h+750℃×4 h)and long-term aging at 750℃for 100-4000 h.The results show that with the extension of aging time,the second phase in the grain and on the grain boundary increases significantly.Due to the precipitation of the second phase particles in the alloy playing a pinning role on the grain boundary,the migration of the grain boundary is inhibited,and the grain size does not grow significantly.The existence of NbC phase and WN phase is found to be the main factors for the microstructure stability of the alloy by SEM and TEM.The strength of the alloy decreases with the increase of aging time,which is mainly affected by the Ostwald ripening mechanism of intragranular dispersed carbides.The increase of hardness of the alloy is related to the precipitation of M 23 C 6 carbides.The coarse M 23 C 6 carbides at the grain boundaries lead to a decrease in the elongation of the alloy with increasing aging time,and the fracture morphology exhibits brittle fracture characteristics.
作者
苑庆德
朱治愿
冯迪
徐超凡
徐锦文
贾俊波
王天宏
Yuan Qingde;Zhu Zhiyuan;Feng Di;Xu Chaofan;Xu Jinwen;Jia Junbo;Wang Tianhong(School of Materials Science and Engineering,Jiangsu University of Science and Technology,Zhenjiang Jiangsu 212100,China;Institute of Materials,Henan Academy of Sciences,Zhengzhou Henan 450053,China)
出处
《金属热处理》
北大核心
2025年第8期91-95,共5页
Heat Treatment of Metals
基金
钢铁研究总院有限公司自主投入研发专项基金(事24G60740Z)。
关键词
高温合金
长期时效
析出相
力学性能
superalloy
long-term aging
precipitation
mechanical properties
作者简介
苑庆德(1998-),男,硕士研究生,主要研究方向为双相不锈钢,E-mail:2609858153@qq.com;通信作者:朱治愿,教授,博士,E-mail:salanganezhu@just.edu.cn。
