试验表明,耐热钢和合金在高温长期应力作用下,由于内部组织变化会出现蠕变脆性现象。事实表明:对耐热钢和合金的高温断裂寿命评定,特别是在缺口蠕变断裂时应采用持久强度和高温蠕变断裂韧性相结合的性能指标,但目前尚缺乏能反映耐热材料在高温长期应力作用下脆性特性指标。蠕变断裂过程实际上是蠕变裂纹萌生和扩展过程。文献[5～8]认为:当裂纹尖端区蠕变损伤积累 Experiments show that heat-resistant steel and alloy under long-term high temperature stress, due to changes in the internal structure will appear creep brittle phenomenon. The facts show that the evaluation of the high temperature rupture life of heat-resisting steel and alloy, especially when the creep rupture is notched, should be based on the combination of long-term strength and creep rupture toughness at high temperature. However, Long-term stress under the brittle characteristics of indicators. Creep rupture process is actually the initiation and propagation of creep cracks. Literature [5 ~ 8] that: when the crack tip area creep damage accumulation