摘要
本文以50 kg真空感应熔炼的镍基合金Ni-24Fe-14Cr-8Mo为实验材料,通过采取不同温度、不同时间的高温扩散热处理,结合光学显微镜、扫描电子显微镜、电子探针分析仪以及金相照片图像分析的手段,围绕温度和时间对合金组织中Laves相回溶以及元素偏析的影响开展研究。结果表明,合金枝晶间岛状低熔点金属间化合物Laves相的析出造成严重的元素偏析,Laves相初熔温度在1 180~1 200℃;在1 180℃7~100 h扩散热处理时,Laves相体积分数随处理时间呈V_f=11.557 8exp(-0.143 2 t)的指数规律减小,在1 180℃保温40 h以内Laves相不能完全回溶,而保温76 h以上则Laves相可以完全回溶,保温100 h可以进一步消除元素偏析。Ni-24Fe-14Cr-8Mo合金的高温扩散热处理温度不应高于Laves相初熔温度,采取1 180℃保温100 h有效地减少Laves相比例以及元素偏析。
In this paper,the influence of high temperature diffusion heat treatment on Laves phase and elements segregation in 50 kg vacuum induction melted Ni-24Fe-14Cr-8Mo nickel base alloy is studied.The alloy is heat-treated at different temperatures for different times,and the microstructure and element distribution are investigated through Optical Microscope(OM),Scanning Electron Microscope(SEM),Electron Probe Micro-Analyzer(EPMA)and Metallographic Processing(MP).Results indicate that island-shaped Laves phase obviously precipitates in the interdendritic area led to a serious elements segregation.The incipient temperature of Laves phase is at 1180~1200℃.When the alloy is soaked at 1180℃for 7~100 h,the volumn fraction of Laves phase kept decreases with diffusion treatment time in an exponential pattern with V_f=11.5578 exp(-0.1432 t);Laves phase could not be totally dissolved in less than 40 h but almost disappeared after 76 h at 1180℃;elements segregation could be further improved after 100 h high temperature diffusion heat treated at 1180℃.It could be concluded that for Ni-24Fe-14Cr-8Mo alloy the high diffusion heat treatment temperature should not be higher than incipient temperature Laves phase,and a treatment at 1180℃for 100 h could effectively reduce Laves phase fraction and elements segregation.
作者
崔毅
张雲飞
吕达
韩彦光
史远
Cui Yi;Zhang Yunfei;Lv Da;Han Yanguang;Shi Yuan(HESTEEL GROUP Technology Research Institute,Shijiazhuang 050000)
出处
《特殊钢》
北大核心
2020年第6期72-76,共5页
Special Steel
关键词
镍基合金
高温扩散热处理
拓扑密排相
初熔温度
Ni-Based Alloy
High Temperature Diffusion Heat Treatment
TCP Phase
Incipient Melting Temperature
