Inconel 600合金中不同类型晶界处铬的浓度

应用TEM、EDS和EBSD等技术研究了Inconel 600合金在715℃时效过程中不同类型晶界处碳化物的结构、形貌和晶界附近Cr浓度的分布。结果表明，不同类型晶界处碳化物的结构和形貌有较大的不同：在Σ3_c晶界析出的碳化物很少，在Σ3_i晶界析出不规则形状的M₂₃C₆碳化物，在Σ9晶界析出较大的M₂₃C₆碳化物颗粒，在Σ27晶界随机析出粗大的M₇C₃碳化物颗粒。富Cr碳化物在晶界的析出使晶界附近贫铬，在相同的时效条件下晶界的Σ值越高其附近贫铬越严重。随着时效时间的延长各晶界附近贫铬区的宽度不同程度地增大，时效15 h贫铬区的深度最大，时效50 h后深度不同程度地减小。

Chromium Concentration Near Grain Boundaries with Various Characters in Inconel Alloy 600

The structure and morphology of carbides and the concentration of Cr near various type of grain boundaries of Inconel alloy 600 after aging treatment at 715℃ for different time were investigated by means of TEM, EDS and EBSD. The results show that there are obvious differences in structure and morphology of carbides precipitated at grain boundaries. Few carbides precipitated at Σ3_c grain boundary, irregular shape M₂₃C₆ carbides precipitated at Σ3_i grain boundary, and lager M₂₃C₆ carbide particles precipitated at Σ9 grain boundary. The coarse M₇C₃ carbide particles precipitated randomly at Σ27 grain boundaries. The precipitation of Cr-rich carbides causes Cr-depletion near the grain boundaries. Under the same aging conditions, the Cr-depletion is more severe near the grain boundaries of higher Σ value. The width of Cr-depletion zone near the grain boundary increases with the increase of aging time. However, the depth of Cr-depletion zone near the grain boundary reaches the maximum value after aging for 15 h, and then decreases to different degrees after aging for 50 h. Based on the experimental results the effect of grain boundary character on the carbide precipitation and Cr-depletion is discussed.