【摘要】 对镍基高温合金GH4049在不同载荷与不同温度下疲劳小裂纹萌生和扩展进行了试验,利用复型技术和光学显微镜观测了裂纹尺寸演化全过程,发现高温疲劳损伤是一个多裂纹系统,且损伤起始于晶界,寿命前期是以裂纹萌生为主的均匀损伤,后期则为以裂纹扩展、合并为主的局部化损伤。更多还原

【Abstract】 The study of small fatigue cracks initiation and propagation of Nibase superalloy GH4049 under various loading at elevated temperature was carried out. The evolution process of cracks’length was observed by using replication method and optical microscopes.It was found that elevated temperature fatingue damage is a multiple cracks system,and begins with grain boundaries.At the initial stage of fatigue life,crack initiation dominates the damage process.During the final stage the damage is local because of the propatation and coalesence of multiple cracks.更多还原