利用高温金相显微镜动态观察了GH169合金在疲劳/蠕变复合作用下的变形和断裂过程。结果表明,疲劳/蠕变复合作用下的变形方式有晶内滑移、孪生和晶界滑动,其失效方式因显微组织而不同。沿晶裂纹源于晶界滑动在三叉点处产生的W型裂纹和晶界局部形变区,其扩展机制为空洞的形核、聚集长大和相互连接;穿晶裂纹源于晶内形变损伤区,其扩展机制为沿滑移面的剪切断裂。
In situ high temperature metalloscopic observation was made of deformation and fracture for superalloy GH169 under combined action of fatigue and creep. The mode of deformation is revealed as slipping, twinning and grain boundary sliding. The mode of failure is dependent upon microstructure. The intergranular cracks arise from W-type voids produced by strees concentration at triple point which would not be relaxed by interior deformation of grains and local deformed region along grain boundaries, and its propagation mechanism is nucleation, growth and linkage of cavities at grain boundaries. Tranagranular cracks result from deformation damage of grain, and its propagation mechanism is shear rupture along slip plane.
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