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研究了微量元素(C,B,Zr)含量、浇注方式和热处理制度对镍基高温合金GMR235组织和性能的影响,并利用热力学软件计算了合金平衡相图。结果表明:设计合金中主要的平衡相为γ′相、M6C碳化物、一次碳化物MC相、M3B2硼化物、M23C6和γ相基体。C含量为0.18%(质量分数)时铸态合金具有较好的持久性能和高温拉伸性能。添加合金元素B、Zr可明显提高合金的持久寿命、改善持久塑性,抑制碳化物析出,并使碳化物颗粒细化。铸模温度为800℃、出钢温度为1420℃时,合金的综合性能最优。经过5h时效后,合金高温持久寿命明显升高且保持了铸态时的塑性。随着时效时间延长,γ′相粗化使合金高温抗拉伸强度降低。
The effects of trace elements (C, B, Zr) content, casting method and heat treatment on the microstructure and properties of GMR235 nickel-base superalloy were studied. The equilibrium phase diagram of the alloy was calculated by thermodynamic software. The results show that the main equilibrium phases in the designed alloys are γ ’phase, M6C carbide, MC carbide, M3B2 boride, M23C6 and γ phase matrix. When the content of C is 0.18% (mass fraction), the cast alloy has good long-term performance and high-temperature tensile properties. Add alloying elements B, Zr can significantly improve the durability of the alloy, improve the ductility of plastic, inhibit the precipitation of carbides, and the carbide particles refinement. When the mold temperature is 800 ℃ and tapping temperature is 1420 ℃, the alloy has the best overall performance. After 5h aging, the alloy high temperature life expectancy increased significantly and maintain the plasticity of the as-cast. With the aging time, γ ’coarsening of the alloy high temperature tensile strength decreased.