合金元素对新型镍基粉末高温合金的热力学平衡相析出行为的影响

通过热力学平衡相计算方法,系统研究了某新型镍基粉末高温合金时效温度下合金元素对热力学平衡相析出行为的影响.计算结果表明:René104合金析出的主要平衡相为γ′、MC、M23C6、M3B2和TCP相.Cr和Co含量主要影响TCP相的析出行为及γ′相的析出温度,Cr含量对M23C6和M3B2的析出行为有一定的影响,Cr的建议质量分数为13%;Mo和W含量影响TCP相和M3B2的析出行为.质量比Al/Ti和Nb/Ta影响γ′相的析出行为,建议控制Al/Ti和Nb/Ta比平衡,以使γ′相起到理想的强化效果.C和B含量显著影响碳化物和硼化物的析出量,还可间接抑制TCP相析出;Zr含量对MC和M23C6碳化物的析出有影响;增Co降Cr和调节合金元素含量以获得小的点阵错配度是第3代涡轮盘用粉末冶金高温合金成分优化设计的趋势.

Effect of alloy elements on the precipitation behavior of thermodynamic equilibrium phases in new type nickel-based P/M superalloys

The effects of alloy elements on the precipitation behaviors of equilibrium phases in new type nickel-based powder metallurgy (P/M) superalloys at aging temperature were studied systematically by a thermodynamic calculation method. The calculation results show that the equilibrium precipitation phases of René104 are γ', MC, M_(23)C_6, M_3B_2 and TCP phases. Cr and Co contents mainly influence the precipitation behaviors of TCP phases and the precipitation temperature of γ' phase. Cr content also plays a role in the precipitation behaviors of M_(23)C_6 and M_3B_2. The suggested content of Cr is 13 % . Mo and W contents influence the precipitation behaviors of TCP phases and M_3B_2. The mass ratios of A1/Ti and Nb/Ta affect the precipitation behaviors of γ' phase. It suggests controlling the values of Al/Ti and Nb/Ta to be unity in order to make γ' phase having desire strengthen effect. C and B contents significantly influence the precipitation volumes of carbides and borides; they can restrain the precipitation of TCP phases indirectly. Zr content influences the precipitation behaviors of MC and M_(23)C_6. Besides, it is revealed that the composition optimization and design trend of the 3rd generation P/M turbine disc superalloys is with more Co, less Cr and to obtain a smaller lattice mismatch by adjusting the contents of alloy elements.