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研究了晶粒细化对K417G高温合金在760℃/645 MPa,900℃/315 MPa和950℃/235 MPa下的蠕变性能的影响.结果表明,晶粒细化对合金蠕变性能的影响与温度和施加应力有关.在760℃/645 MPa下合金的蠕变性能随晶粒细化而提高,变形以晶内变形为主;900℃/315 MPa下的蠕变性能随晶粒细化先升高后降低,变形为晶内变形和晶界滑移竞争作用;950℃/235 MPa下的蠕变性能随晶粒细化而降低,变形以晶界滑移为主.760℃/645 MPa下,位错切过g’相,基体通道中没有位错网产生;900℃/315 MPa和950℃/235 MPa下位错通过Orowan机制绕过g’相,基体通道中产生位错网,并且M23C6在晶内析出.
The effects of grain refinement on the creep properties of K417G superalloy at 760 ℃ / 645 MPa, 900 ℃ / 315 MPa and 950 ℃ / 235 MPa were investigated. The results show that the effect of grain refinement on the creep properties of the alloy Which is related to the temperature and applied stress.The creep property of the alloy increases with the grain refinement at 760 ℃ / 645 MPa, and the deformation is dominated by the intragranular deformation. The creep property at 900 ℃ / 315 MPa decreases with the grain refinement The deformation at 950 ℃ / 235 MPa decreases with the grain refinement, and the deformation is dominated by grain boundary slip.760 ℃ / 645 Dislocations cut through the g ’phase and there was no dislocation network in the matrix channel. The dislocations were bypassed the g’ phase by Orowan mechanism at 900 ℃ / 315 MPa and 950 ℃ / 235 MPa, And M23C6 precipitation in the crystal.