Quan Qiongrui, Sun Shijie, Sheng Naicheng, Deng Juan, Hou Guichen, Li Jinguo, Chen Jidong, Zhou Yizhou, Sun Xiaofeng
AECC Aero Science and Technology Co., Ltd., Chengdu 61000, China.
Shi-changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
Materials (Basel). 2022 Oct 26;15(21):7509. doi: 10.3390/ma15217509.
The effect of the Mo contents of 1.0 wt.%, 1.5 wt.%, 2.0 wt.%, and 3.0 wt.% on the microstructures and mechanical properties of the polycrystalline superalloy with a high W content was studied. The typical dendrite morphology was observed in the high-W superalloy with different Mo contents, containing γ matrix, γ' phase, eutectic, and MC carbide. After the heat treatment, the primary MC carbides were decomposed into MC carbides, while a needle-like topologically close-packed (TCP) phase was formed in the alloy with high Mo content, in contrast to the other three alloys with low Mo content. The Mo addition increased the lattice parameter of the γ and γ' phases and also changed the lattice misfits of the γ and γ' phase lattice misfits towards a larger negative. The addition of Mo improved the yield strength at room temperature due to the solid solution strengthening and coherency strengthening. The improvement of the stress rupture lives at 975 °C/225 MPa was due to the combination of the suppressed propagation of the microcracks by the carbides and a more negative misfit. When the Mo content reached 3.0 wt.%, the TCP phases formed and decreased the ultimate tensile strength and the stress rupture lives as a result.
研究了1.0 wt.%、1.5 wt.%、2.0 wt.%和3.0 wt.%的Mo含量对高W含量多晶高温合金微观组织和力学性能的影响。在不同Mo含量的高W高温合金中观察到典型的枝晶形态，包括γ基体、γ'相、共晶和MC碳化物。热处理后，初生MC碳化物分解为MC碳化物，而与其他三种低Mo含量合金相比，高Mo含量合金中形成了针状拓扑密排（TCP）相。Mo的添加增加了γ和γ'相的晶格参数，也使γ和γ'相晶格错配朝着更大的负值变化。由于固溶强化和共格强化，Mo的添加提高了室温屈服强度。975 °C/225 MPa下持久寿命的提高是由于碳化物抑制微裂纹扩展和更大的负错配共同作用的结果。当Mo含量达到3.0 wt.%时，TCP相形成，导致抗拉强度和持久寿命降低。
