摘要
利用超音速火焰喷涂技术在Ni718合金表面制备WC-17Co涂层.利用反复弯曲试验分析25,150,300℃条件下涂覆WC-17Co涂层Ni718合金疲劳性能,利用扫描电镜、X射线衍射仪分析涂层的断口形貌和相组成,并利用剥层法测量涂层中残余应力分布.结果表明,相同应变量条件下试样的疲劳寿命随着温度的升高而降低;循环载荷作用下裂纹由涂层表面产生,向基体方向扩展,最终形成整体断裂;室温至300℃温度范围内,涂层不会发生相变,但是随环境温度上升涂层中的残余压应力呈现下降趋势,这种趋势使得涂层中裂纹的扩展速度增加,最终导致疲劳寿命下降.
The WC-17Co coating was deposited on the Inconel 718 alloy by high-velocity oxygen fuel(HVOF) thermal spray method.The phase composition and fracture of WC-17Co coatings were investigated by XRD method and SEM,respectively.The bending fatigue behaviors of cantilever specimens were also discussed.The effects of ambient temperature(25,150,300 ℃) on the bending fatigue life were studied in this paper as well.The results showed that fatigue cracks were initiated on the surface coating,then propagated toward the substrate/coating interface,and finally penetrated into the substrate.The bending fatigue life of the coated specimen decreased with the increase of ambient temperature.The average compressive residual stress of WC-17Co coatings decreased after heat treatment.Therefore,a higher crack-propagation rate was induced in the surface coating,resulting in the lower fatigue life of the coated specimen.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2014年第2期87-90,117,共4页
Transactions of The China Welding Institution
基金
工信部重大专项资助项目(2011zx04014-21)
