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本文研究指出,微量元素Mg能大幅度地提高GH698合金的蠕变断裂时间及断裂塑性,在不明显影响最小蠕变速率条件下延长蠕变第二和第三阶段的持续时间。Mg对高温1Hz下的拉压对称疲劳无影响,但一旦存在疲劳蠕变交互作用,Mg的有利作用就显示出来了。AES分析了Mg在蠕变过程中行为,在无应力条件下晶界偏聚的Mg,在蠕变应力作用下,晶界Mg偏聚先均匀化,再向蠕变孔洞富集,同时有减少S偏聚的倾向,导致减慢蠕变孔洞长大速率,延长蠕变第二和第三阶段。
This study indicates that the trace element Mg can significantly improve the creep rupture time and fracture plasticity of GH698 alloy and prolong the duration of the second and third stages of creep without significantly affecting the minimum creep rate. Mg has no effect on the tension and compression symmetry fatigue at high temperature of 1 Hz, however, once the fatigue-creep interaction exists, the beneficial effect of Mg is revealed. AES analysis of Mg in the creep process, under stress-free grain boundary segregation of Mg, under the effect of creep stress, the grain boundary Mg segregation homogenization before enrichment creep pores, while reducing S tends to segregate, leading to slowing the rate of creep hole growth and prolonging the second and third stages of creep.