摘要
采用低压等离子喷涂技术在镍基单晶高温合金上制备了NiCoCrAlYTa涂层,研究了在大气环境870℃高温、轴向应力控制方式和应力比R=0.1条件下,有涂层的镍基单晶的高周疲劳性能,并与无涂层的镍基单晶高周疲劳性能进行了比较。通过失效分析,对有涂层的镍基单晶疲劳裂纹源形成与扩展机制进行了初步探讨。结果表明,有涂层的镍基单晶疲劳极限为480MPa,无涂层的镍基单晶疲劳极限为440MPa,涂层提高了镍基单晶基体疲劳极限,提高幅度约9.1%。在480MPa至580MPa应力幅范围内,有涂层的镍基单晶疲劳寿命高于无涂层镍基单晶。有涂层的镍基单晶疲劳断裂试样的裂纹源均来自基体内部,疲劳寿命主要取决于疲劳裂纹源孕育及形成寿命。
The NiCoCrAlYTa coatings were prepared on Ni-base single crystal super-alloy by low pressure plasma spraying(LPPS). High-temperature high cycle fatigue property of NiCoCrAlYTa coating on Ni-base single crystal super-alloy at 870℃ was investigated and compared with that of uncoated Ni-base single crystal super-alloy. Fatigue failure mechanisms of the coatings at 870℃ were studied. The result shows that fatigue limit of NiCoCrAlYTa coating on Ni-base single crystal super-alloy is better than uncoated Ni-base single crystal super-alloy,the increase of fatigue limit is 9.1%. Fatigue life of coated Ni-base single crystal super-alloy is longer than that of uncoated under the range of stress amplitude from 480MPa to 580MPa. Fatigue fracture indicates fatigue cracks initiators of high cycle fatigue coated specimen were initiated within Ni-based single crystal super-alloys. It’s fatigue life depends on formation of fatigue cracks initiators.
出处
《热喷涂技术》
2009年第1期34-38,共5页
Thermal Spray Technology
