STUDY ON FRACTURE OF SUPERPLASTIC DEFORMATION IN LF6
Long Nidong(The Air Force College of Engineering)
The microstructural change and fracture morphology during superplastic deformation of LF6 Alumini-um alloy have been examined. The experimental results show that cavities mainly nucleate at triple points and grow continuously with the increase of strain, at the same time, new cavities occllred. Grain boundarysliding is the main cause of cavity growth. Because of high strain rate sensitivity, the alloy can preventcavitise from propagation and interlinkage along transverse grain boundaries. Only at the later stage of de-formation, cavities begin to interlink and propagate extensively along transverse grain boundaries, which isdue to the increase in local stress of the weakpart of the tensile sample, causing the fracture of the alloy.The grain growth and elongation in the tension direction during deformation may promote cavity nucle-ation. A physical model of superplastic de formation fracture of the alloy is presented.
【CateGory Index】： V25