首页|新型高温合金21Cr-32Fe-41Ni高温长期时效组织演变研究

新型高温合金21Cr-32Fe-41Ni高温长期时效组织演变研究

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铁镍基合金长期服役于较高温度下,因此高温下的组织稳定性是合金的重要指标之一.利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、电子探针(EPMA)、化学相分析等手段对750 ℃不同时效时间下新型铁镍基高温合金21Cr-32Fe-41Ni组织与性能演变规律进行研究.结果表明,长期时效后合金中析出相主要有γ'相、σ相、α-Cr相以及MC相.在时效500 h内,基体中弥散分布的球形γ'相的质量分数和尺寸快速增加.时效时间从500 h增加至2000 h,γ'相的质量分数和尺寸增加速率逐渐降低.在长期时效过程中,σ相沿晶呈块状或条状分布,并与α-Cr相同时在晶内以针状或条状析出.随时效时间增加,σ相和α-Cr相数量增加,逐渐粗化.沿晶不连续分布的σ相逐渐相连,存在向网状分布发展的趋势.随时效时间增加至2000 h,合金强度先升高后降低,在时效500 h后达到峰值,硬度保持增加趋势.
Microstructure Evolution of New Superalloy 21Cr-32Fe-41Ni During Long-Term Aging at High Temperature
Fe-Ni based alloys serve in high temperature environment for a long time,so the microstructure stability at high temperature is one of the important indexes of the alloys.The microstructure and properties evolution of a new Fe-Ni based superalloy 21Cr-32Fe-41Ni at 750 ℃ for different aging time were investigated by scanning electron microscope(SEM),transmission electron microscope(TEM),electron probe microanalysis(EPMA)and chemical phase analysis.The results show that the precipitates in the alloy are mainly γ',σ,α-Cr,and MC phases after long-term aging.The mass fraction and size of the dispersed spherical y'in the matrix are increased rapidly within 500 h aging.With the increase in aging time from 500 h to 2000 h,the increase rate of mass fraction and size of y'gradually decreases.During the long-term aging process,the σ phases are distributed along the grain boundaries in block or strip shape and within grains in needle or strip shape.The distribution of α-Cr phases in the grains is the same as that of σ phases.With the increase in aging time,the number of σ and α-Cr phases is increased and they are gradually coarsened.The σ phases with discontinuous distribution along the grain are gradually connected,and there is a tendency to develop into a network distribution.With the increase in aging time to 2000 h,the strength of the alloy increases first and then decreases,and reaches the peak after aging for 500 h.While,the hardness keeps increasing.

Fe-Ni based alloylong-term agingγ'phaseσ phaseα-Cr phase

李天宇、王立民

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钢铁研究总院特殊钢研究院,北京 100081

铁镍基合金 长期时效 γ'相 σ相 α-Cr相

国家重点研发计划国家自然科学基金

2017YFB030520351971226

2024

稀有金属材料与工程
中国有色金属学会,中国材料研究学会,西北有色金属研究院

稀有金属材料与工程

CSTPCD北大核心
影响因子:0.634
ISSN:1002-185X
年,卷(期):2024.53(4)
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