有外来扩散源条件下DD402单晶合金中的γ'相筏形化

γ′phase rafting in single crystal DD402 superalloy under element diffusion from outer sources

研究了热等静压(HIP)连接DD402单晶合金与FGH95粉末合金的扩散偶中,DD402单晶合金的γ'相筏形化过程.提出了一种新的γ'相筏形化的机理,分析了γ'相筏形化的驱动力问题,建立了γ'相筏形化过程的物理模型.讨论了筏形γ'片层厚度与原始γ'相的尺寸、体积分数以及γ'相形成元素的扩散流量之间的关系.结果表明,单晶合金的γ'筏形化是由于其形成元素的扩散使γ'定向长大.筏形化的过程包括两个阶段:一是γ'粒子的定向连接阶段;二是筏形γ'片层的平坦化.筏形化γ'的初始片层厚度及筏形化方向主要由γ'原始尺寸及晶体取向决定.

The rafting procedure of γ′ phase in single crystal DD402 for DD402/FGH95 diffusion couples bonded by hot isostatic pressing（HIP） was studied.A new rafting mechanism of γ′ phase was suggested.The driving force of rafting γ′ phase was analyzed and a physical model of the rafting procedure of γ′ phase was constructed.The relations of the width of rafted γ′ phase pieces with the original size,volume fraction and constitutional element diffusion flux of γ′ phase were discussed in details.The results show that the rafted reason of γ′ phase in the single crystal is the continuous directional growth of γ′ phase driven by diffusion of its constitutional elements.The rafted process includes two stages,one is the directional connect of γ′ particles,and the other is the plainness process of γ′ pieces.The width and direction of rafted γ′ pieces were closely related to the original size and crystal orientation of γ′ phase.