摘要
研究了K40S钴基高温合金在700℃和900℃温度条件下由应变控制的高温低周疲劳行为.对循环应力-应变数据和应变-疲劳寿命数据进行了分析,进而给出了K40S合金在此温度范围的疲劳参数.结果表明:与传统X-40合金相比,K40S合金具有优异的抗高温低周疲劳性能;合金的应力-应变响应行为在700℃时,呈现为循环强化,而在900℃时,为初期强化随后软化,且随着总应变幅的增加,强化效果均增强.上述行为归因于循环形变过程中位错-位错;位错-析出相及固溶原子间的相互作用.
Isothermal cyclic deformation tests were conducted on K40S cobalt-base superalloy with total strain amplitude from ±0.1% to ±1.0% at 700℃ and 900℃. Correlations between microscopic cyclic deformation and cycle stress response with various microstructural phenomena were established through scanning electron microscopy (SEM) and transmission electron microscopy (TEM), detailing the deformation substructure and carbide precipitation. The results show that K40S alloy possesses high low cycle fatigue resistance in comparison with X-40 alloy. K40S superalloy exhibits cyclic stress response of cyclic hardening at 700℃, and of initial hardening followed by softening at 900℃. In addition, at both temperatures, cyclic hardening during cycle deformation increases with increasing strain amplitude, while the fatigue lifetime decreases. The cyclic stress response behavior can be rationalized based on the mechanisms associated with dislocation-dislocation interactions, dislocation-precipitate (M23C6) interactions and interactions between the solute atoms and the dislocations.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2002年第10期1047-1052,共6页
Acta Metallurgica Sinica
关键词
疲劳性能
钴基高温合金
高温低周疲劳
位错
cobalt-base superalloy, high temperature low cycle fatigue, dislocation
