Nanosized Cr-N clustering in expanded austenite layer of low temperature plasma-nitrided Fe-35Ni-10Cr alloy
Nanosized Cr-N clustering in expanded austenite layer of low temperature plasma-nitrided Fe-35Ni-10Cr alloy
复制标题
低温等离子氮化 Fe-35Ni-10Cr 合金膨胀奥氏体层中纳米 Cr-N 团簇
DOI：
10.1016/j.scriptamat.2022.114637
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发表时间：
2022
影响因子：
6
通讯作者：
Furuhara Tadashi
中科院分区：
文献类型：
--
作者：
Xie Yulin;Miyamoto Goro;Furuhara Tadashi
奥氏体不锈钢低温氮化形成的扩大奥氏体（γN）是一种含有Cr-N短程有序的富氮面心立方，但尚未直接观察到Cr-N团簇的报道。在本研究中，使用透射电子显微镜 (TEM) 和三维原子探针 (3DAP) 技术研究了在 673K 等离子氮化的 Fe-35Ni-10Cr (at%) 合金的纳米结构。在γN中直接观察到纳米尺寸的Cr-N团簇，并在选区衍射中观察到强烈的条纹，在TEM中观察到明显的调制结构，通过3DAP观察到富Cr-N区域。热力学计算表明，由于强烈的 Cr-N 吸引力相互作用，Cr-N 团簇是通过旋节线分解形成的。 γN层的硬度远高于Fe-N奥氏体钢，这表明其硬度不仅是氮固溶强化的结果，而且是Cr和N共存的协同作用的结果。
Expanded austenite (γN) formed by low temperature nitriding of austenitic stainless steel is a N-enriched fcc containing Cr-N short range ordering, but no direct observation of Cr-N clustering has been reported. In the present study, the nanostructure of an Fe-35Ni-10Cr (at%) alloy plasma-nitrided at 673 K was investigated using transmission electron microscopy (TEM) and three-dimensional atom probe (3DAP) technique in this study. Nanosized Cr-N clusters were directly observed in the γNaccompanied with strong streaks in selected area diffraction, obvious modulated structure in TEM and Cr-N rich regions observed by 3DAP. Thermodynamic calculations suggested that Cr-N clusters were formed by spinodal decomposition due to a strong Cr-N attractive interaction. The hardness of the γNlayer was much higher than that of Fe-N austenite steel, which indicates that the hardness is not only due to nitrogen solid-solution hardening but also to a synergetic effect of the coexistence of Cr and N.