金属热处理 ›› 2025, Vol. 50 ›› Issue (8): 91-95.DOI: 10.13251/j.issn.0254-6051.2025.08.016

• 材料研究 • 上一篇    下一篇

长期时效对21-4NWNbMoCu合金组织和性能的影响

苑庆德1, 朱治愿2, 冯迪1, 徐超凡1, 徐锦文1, 贾俊波1, 王天宏1   

  1. 1.江苏科技大学 材料科学与工程学院, 江苏 镇江 212100;
    2.河南省科学院 材料研究所, 河南 郑州 450053
  • 收稿日期:2025-03-08 修回日期:2025-07-02 出版日期:2025-08-25 发布日期:2025-09-10
  • 通讯作者: 朱治愿,教授,博士,E-mail:salanganezhu@just.edu.cn
  • 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。
  • 基金资助:
    钢铁研究总院有限公司自主投入研发专项基金(事24G60740Z)

Effect of long-term aging on microstructure and properties of 21-4NWNbMoCu alloy

Yuan Qingde1, Zhu Zhiyuan2, Feng Di1, Xu Chaofan1, Xu Jinwen1, Jia Junbo1, Wang Tianhong1   

  1. 1. School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang Jiangsu 212100, China;
    2. Institute of Materials, Henan Academy of Sciences, Zhengzhou Henan 450053, China
  • Received:2025-03-08 Revised:2025-07-02 Online:2025-08-25 Published:2025-09-10

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M23C6型碳化物持续析出相关;晶界处粗大M23C6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。

关键词: 高温合金, 长期时效, 析出相, 力学性能

Abstract: 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 M23C6 carbides. The coarse M23C6 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.

Key words: superalloy, long-term aging, precipitation, mechanical properties

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