摘要
K4002合金是目前广泛使用的一种镍基铸造高温合金,其技术标准中对痕量元素Se含量未做控制要求。同时,已有研究表明Se对不同合金的影响规律不尽相同。为阐明元素Se对K4002合金组织和性能的影响,通过热力学软件计算了K4002合金的平衡析出相,并研究了痕量元素Se对K4002合金组织和性能的影响规律。结果表明,K4002合金的主要平衡析出相为基体γ相、γ′相、M_(3)B_(2)型硼化物、碳化物(MC型、M_(6)C型和M_(23)C_(6)型)及少量的Ni5Hf相。MC型碳化物富集Hf、Ta元素,M_(23)C_(6)型碳化物富集Cr元素,M_(6)C型碳化物主要富集W元素同时含有一定量的Ni和Cr元素,M_(3)B_(2)型硼化物主要富集W元素同时含有一定量的Cr元素。随Se含量的升高,K4002合金的平均持久寿命呈现逐渐下降的趋势。这是由于晶界处偏聚的Se元素不断增多并逐渐形成低熔点相甚至是显微疏松,削弱了晶界的强度。应将K4002合金中的Se元素含量控制在3×10^(-6)以下.
K4002 alloy is a widely used nickel-based superalloy,and the trace element Se content is not controlled by its technical standards.Moreover,existing studies have shown that the effects of Se on different alloys are not the same.To determine the influences of Se on the structures and properties of the K4002 superalloy,the equilibrium precipitated phases of the K4002 superalloy were calculated by thermodynamic software,and the effects of Se on the microstructure and properties of the K4002 alloy were studied.The results show that the main equilibrium precipitates of the K4002 alloy are the matrixγphase,γ′phase,M_(3)B_(2)type borides,carbides(MC type,M_(6)C type and M_(23)C_(6)type)and a small amount of the Ni5Hf phase.MC-type carbides are enriched in Hf and Ta,M_(23)C_(6)-type carbides are enriched in Cr,M_(6)C-type carbides are mainly enriched in W and contain a certain amount of Ni and Cr,and M_(3)B_(2)-type carbides are mainly enriched in W and contain a certain amount of Cr.With increasing Se content,the average durability life of the K4002 alloy decreases gradually.This is due to the continuous increase in Se segregation at the grain boundaries and the gradual formation of low-melting point phases and even microscopic pores,which weakens the strength of the grain boundaries.The Se content in the K4002 alloy should be controlled below 3×10^(-6).
作者
刘东方
冯微
马秀萍
张凤祥
李溪伦
孟宇
LIU Dongfang;FENG Wei;MA Xiuping;ZHANG Fengxiang;LI Xilun;MENG Yu(Division of Superalloy Melting&Casting,Baimtec Material Co.,Ltd.,Beijing 100094,China;Center of Melting&Casting,AECC Beijing Institute of Aeronautical Materials,Beijing 100094,China)
出处
《铸造技术》
CAS
2024年第7期681-686,共6页
Foundry Technology
基金
国家重点研发计划青年科学家项目(2022YFB3708100)。
关键词
热力学计算
痕量元素
K4002合金
Se元素
组织和性能
thermodynamic calculations
trace elements
K4002 superalloy
Se element
structure and properties
