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选用950℃时效温度,对DZ125定向凝固高温合金进行了500、1 000、1 500h的长期时效。利用超声疲劳试验机测试了合金的超高周疲劳性能。采用扫描电子显微镜、透射电子显微镜和电子背散射衍射(EBSD)研究了合金的显微组织和超高周疲劳行为。结果表明:长期时效对DZ125合金的组织稍有影响,长期时效后合金的点阵错配度降低,随着时效时间的延长,γ′相聚集长大更加明显,未出现拓扑密排相(TCP)等有害相;长期时效对DZ125合金的超高周疲劳性能稍有影响,随着时效时间的延长,疲劳性能呈下降趋势,疲劳断口较平整,裂纹起源于试样的表面,在超高周疲劳后合金的晶粒发生了小幅度旋转。
Select aging temperature of 950 ℃, DZ125 directional solidification superalloy 500,1 000,1 500h long-term aging. Ultrahigh cycle fatigue properties of the alloy were tested by ultrasonic fatigue testing machine. The microstructure and super-cycle fatigue behavior of the alloy were investigated by scanning electron microscopy, transmission electron microscopy and electron backscatter diffraction (EBSD). The results show that the long-term aging has a slight effect on the microstructure of DZ125 alloy, and the lattice mismatch of the alloy decreases after long-term aging. As the aging time increases, the γ ’phase aggregates and grows more obviously. ) And other harmful phases. The long-term aging has a slight effect on the ultrahigh-cycle fatigue performance of DZ125 alloy. With the increase of aging time, the fatigue performance shows a downward trend, the fatigue fracture is smooth, the cracks originate on the surface of the sample, After fatigue the grain of alloy has a small rotation.