【摘要】 制备了[001]和[111]取向的Ni₃Al基单晶高温合金，测试了合金在980℃/186 MPa和1040℃/135 MPa条件下的持久性能，分析了晶体取向对合金持久性能的影响。结果表明：固溶时效处理后，[001]取向试样中γ′相呈立方体，[111]取向试样截面的γ′相呈三角形，两试样中的γ′相体积分数约为70%;在980℃/186 MPa和1040℃/135 MPa条件下，[111]取向试样表现出较高的持久寿命，分别是510.81 h和285.36 h,为[001]取向试样的12.6倍和17.6倍；在高温低应力条件下，两种取向试样的断裂模式均为微孔聚集型断裂，[001]取向试样持久断裂后γ′相发生P型筏化，[111]取向试样无特定筏化方向；[111]取向试样中独特的γ/γ′筏形结构、致密的界面位错网、低Schmid因子导致滑移系难以开动等因素提高了持久变形抗力。更多还原

【Abstract】 Ni₃Al-based single crystal superalloys with [001] and [111] orientations were prepared, and the stress rupture property of the alloys was tested at 980 ℃/186 MPa and 1040 ℃/135 MPa, respectively, and the effect of crystal orientation on the stress rupture property of the alloys was analyzed. The results show that after solution and aging treatment, the γ′ phase in the [001] oriented specimen is cubic, the γ′ phase on the section in the [111] oriented specimen is triangular, and the volume fraction of the γ′ phase in the two specimens is about 70%. Under the conditions of 980 ℃/186 MPa and 1040 ℃/135 MPa, the [111] oriented specimens show higher stress rupture lifetimes, which are 510.81 h and 285.36 h, 12.6 and 17.6 times higher than that of the [001] oriented specimens. Under high temperature and low stress conditions, the fracture modes of both oriented alloys are microvoid coalescence fracture, with P-type rafting of the γ′ phase occurring in the stress rupture of the [001] oriented specimen, and no specific rafting direction for the [111] oriented specimen. The distinctive γ/γ′ rafting structure in the [111] oriented specimen, the dense interfacial dislocation networks, and low Schmid factor that make it difficult to activate the slip systems, thus improving the stress rupture deformation resistance.更多还原