在V20焊态样品中的枝晶间区域未检测到局部富集的 C，如图（a）所示。然而，根据V20焊后热处理样品中具有相应 C 元素分布图的背散射电子图像，观察枝晶间区域 C 元素的富集是明显的，如图（b）所示，表明大量析出相很可能在枝晶间处析出。

The resultant elemental map for C element clearly revealed that no locally enriched C was detected at ID region in the V20 AW specimen, as shown in Fig (a). However, according to the back-scattered electron image with corresponding C elemental distribution map in the V20 PWHT specimen, it is of interest to observe the enrichment of C elements at ID region, as illustrated in Fig (b), suggesting that a large number of precipitates were likely located at ID region.