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在高温度梯度真空定向凝固炉中,采用螺旋选晶法制备了不含Y和含0.01%Y的两种单晶高温合金,研究了稀土Y对单晶高温合金组织以及在980℃/300 MPa条件下持久性能的影响。结果表明,添加微量稀土Y后,单晶高温合金的固相线和液相线降低,合金的一次枝晶间距有减小趋势,铸态和热处理γ′相均有所减小。在1100℃时效200 h后,不含Y和含Y合金都发生了γ′相的长大粗化以及少量针状TCP相的析出,而含Y合金的γ′相粗化程度较轻,Y对TCP相的析出无明显影响。添加微量稀土Y后,合金的高温持久性能提高。最后讨论了加入稀土Y提高单晶高温合金持久性能的原因。
In a high temperature gradient vacuum solidification furnace, two kinds of single crystal superalloy Y and Y containing 0.01% Y were prepared by spiral selective crystal method. The effect of rare earth Y on the microstructure of single crystal superalloy and the microstructure of the as-grown single crystal superalloy at 980 ℃ / 300 MPa The impact of lasting performance under conditions. The results show that the solidus and liquidus of the single crystal superalloy decrease with the addition of trace amount of rare earth Y. The primary dendritic spacing decreases and the γ ’phase in as-cast and heat treated alloys decreases. After aging at 1100 ℃ for 200 h, the coarse and coarse γ ’phase coarsening and the precipitation of a small amount of needle-like TCP phase occurred. However, the γ’ phase of the Y-containing alloy was less coarsened and the Y No significant effect on the precipitation of TCP phase. Adding a trace amount of rare earth Y, the alloy’s high temperature durability. Finally, the reasons why the addition of rare earth Y to improve the long-term performance of single crystal superalloy were discussed.