Cu对Fe-NiAlMn合金析出强化过程的影响

Effect of Cu on precipitation strengthening process in Fe-NiAlMn alloy

将Fe-NiAlMn和Fe-CuNiAlMn合金在900℃固溶2 h后水淬,并在500℃时效不同时间。利用显微硬度测试和原子探针层析技术(APT)研究Cu的添加对Fe-NiAlMn合金析出强化过程的影响。结果表明:Cu的添加增强了时效初期的析出强化效果,加快了整个析出强化进程。时效过程中,Cu元素首先偏聚形核成为富Cu相,并促使Ni,Al,Mn元素在富Cu相与基体界面处偏聚形核形成Ni(Al,Mn)相,两相为核壳结构。随着时效时间的延长,富Cu相由BCC结构转变为FCC结构,与Ni(Al,Mn)相逐渐分离。

Fe-NiAlMn and Fe-CuNiAlMn alloys were aged at 500℃for different time after solution treatment at 900℃for 2 h and water quenching.The influence of Cu-addition on the precipitation strengthening in Fe-CuNiAlMn alloy was studied using hardness testing and atom probe tomography(APT).The results show that the addition of Cu effectively enhances the effect of precipitation strengthening in the early stage of aging and accelerates the whole process of precipitation strengthening.Cu elements first segregate to form Cu-rich phase,which promotes Ni,Al and Mn elements to segregate and nucleate at the interface between Cu-rich phase and matrix to form Ni(Al,Mn)phase resulting in core-shell structure during aging.With the extension of aging time,Cu-rich phase changes from BCC to FCC and separates from Ni(Al,Mn)phase.