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用光学显微镜观察了沿 [0 0 1],[0 11]和 [111]方向生长的镍基单晶高温合金的枝晶形态。结果表明 ,以枝晶界面生长的单晶中生长方向完全由择优取向〈0 0 1〉决定 ,[0 0 1]方向中形成平行于轴向的枝晶 ,[0 11]和 [111]方向中由于不同取向的枝晶交错生长 ,形成多种位向的亚晶界。在垂直于枝晶方向的 { 0 0 1}面内测定的一次枝晶间距 ,按 [0 0 1]→ [0 11]→ [111]次序增大。用电子探针测定了不同取向中合金元素的偏析比 ,Al,Co ,W的偏析情况不受晶体取向影响 ,Ti和Cr的偏析比按 [0 0 1]→ [0 11]→ [111]的顺序减小 ,Ta和Mo的偏析程度无确切变化规律。各元素在不同取向中偏析的变化是由元素的扩散能力和枝晶空间构形共同决定的。
The dendritic morphology of the nickel base single crystal superalloy grown in [0 0 1], [0 11] and [111] directions was observed with an optical microscope. The results show that the growth direction in the single crystal grown at the dendrite interface is completely determined by the preferred orientation <0 0 1>, and the dendrite parallel to the axial direction [0 0 1], [0 11] and [111] Due to the different orientation dendritic staggered growth, the formation of a variety of sub-oriented sub-boundaries. The primary dendrite spacing measured in the {0 0 1} plane perpendicular to the dendrite direction increases in the order of [0 0 1] → [0 11] → [111]. The segregation ratio of alloying elements in different orientations was measured by electron probe. The segregation of Al, Co and W was not influenced by the crystal orientation. The segregation ratio of Ti and Cr was calculated as [0 0 1] → [0 11] → [111] The order of reduction, Ta and Mo segregation degree without exact changes. The segregation of elements in different orientations is determined by the diffusivity of elements and the spatial configuration of dendrites.