摘要
利用SEM观察了一种Ni基单晶高温合金[001]方向持久断裂的断口、纵向剖面和变形后的组织结构.结果表明:在760-1100℃温度范围内,合金的断裂均属于韧性断裂.在低于800℃的低温高应力下,合金中的γ’相不形成筏形组织,合金的断裂特征为纯剪切型断裂,对显微疏松缺陷不敏感;随着温度的增加和应力的降低, γ’相逐渐发生定向粗化,形成筏形结构,合金的持久断裂逐渐转变为微孔聚集型断裂,气孔和疏松成为主要的裂纹源.
Stress rupture characteristics of a Ni base single crystal superalloy at different test conditions were investigated its fracture surface and longitudinal sections were examined by SEM. The results show that the fracture behavior of the alloy belongs to ductile fracture at range of 760-1100 degreesC. At low temperature (<800 degreesC) and high stress, gamma' particles remain cubic shape, the fracture mode is pure shear fracture, and the alloy is not sensitive to the shrinkage porosity. At high temperature and low stress, directional coarsening of gamma' phases occurs, fracture mode turns to be microvoid coalescence fracture and the alloy is sensitive to the shrinkage porosity.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2004年第8期858-862,共5页
Acta Metallurgica Sinica
关键词
NI基单晶高温合金
持久断裂
剪切
微孔聚集
Ni base single crystal superalloy
stress rupture
shear
microvoid coalescence
