摘要
以不同P元素含量的GH4738合金为研究对象,利用扫描电镜、透射电镜、EBSD技术以及分子动力学模拟研究高温持久载荷下不同P含量对GH4738合金持久性能的影响机理。持久实验表明,P添加量从0.004%(质量分数,下同)增加至0.0091%时,合金的持久寿命增加;继续添加P元素,合金持久性能下降。微观分析及分子动力学模拟结果表明,P倾向偏聚于晶界,可以增加晶界的内聚力及结合能,同时与晶界碳化物共同影响GH4738合金的持久性能。P元素含量从0.004%增加至0.0091%时,晶界析出的M_(23)C_(6)碳化物由少量且离散分布的状态逐渐增加并呈不连续链状分布,持久变形时晶界碳化物对位错的钉扎作用增强,能有效地抑制位错运动,此时合金的持久性能较高。但当P含量进一步增加至0.019%时,晶界M_(23)C_(6)碳化物有连接成片的趋势,合金持久性能降低。
An investigation is conducted into the mechanisms by which varying levels of phosphorus(P)affect the high-temperature properties,particularly the stress rupture properties,of GH4738 alloy.This is achieved through the use of scanning electron microscopy(SEM),transmission electron microscopy(TEM),electron backscatter diffraction(EBSD)analysis,and molecular dynamics simulations.Stress rupture experiments reveals that the optimal stress rupture properties of GH4738 alloy are obtained when the phosphorus content is increased from 0.004%(mass fraction)to 0.0091%.Beyond this range,an increase in phosphorus content lead to a decline in stress rupture properties.Further microstructural analysis and molecular dynamics simulations demonstrates that phosphorus tends to segregate at grain boundaries,enhancing the cohesion force and bonding energy of these boundaries.Additionally,phosphorus interacts with carbides at grain boundaries to influence stress rupture properties.Specifically,as the phosphorus content increases from 0.004%to 0.0091%,M_(23)C_(6) carbides at grain boundaries gradually transition from a small,discrete distribution to a discontinuous chain-like distribution.This enhances the pinning effect on dislocations,effectively suppressing their movement and resulting in improved stress rupture properties.However,when the phosphorus content reaches a certain threshold,such as 0.019%,the morphology of M_(23)C_(6) carbides at grain boundaries changes to a plate-like shape,leading to a decrease in stress rupture properties.
作者
刘慧鑫
马亚芬
荣义
罗志强
曲敬龙
张麦仓
LIU Huixin;MA Yafen;RONG Yi;LUO Zhiqiang;QU Jinglong;ZHANG Maicang(School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China;Beijing GAONA Materials&Technology Co.,Ltd.,Beijing 100081,China)
出处
《航空材料学报》
北大核心
2025年第2期37-44,共8页
Journal of Aeronautical Materials
基金
国家重点研发计划资助项目(2021YFB3700403)。
