The simulation for damage of metal powder compacts during forming
The main models of describe metal powder compacting are introduced in this paper. Based on a new model derived from Lee's metal powder compacting model and plastic theory for porous material, the scent of damage status of two-level flanged metal powder compacts during forming is simulated and the damage state and cracking process of compacts in different load process are followed up.
A CRITERION OF DUCTILE DAMAGE IN METALFORMING
Based on Lemaitre's four basic elements, such as damage variable, hypothesis of isotropy, concept of effective stress and hypothesis of strain equivalence, and thermodynamics as well, and also on the author's hypothesis that damage can only be developed on plastic deformation with tensile stress, a new model of isotropic ductile damage was derived. The new model can explain that on the free surface of free homogeneous upsetting there is no ductile fracture.
SR topography of plastically deformed Fe-Si bicrystals - observation in situ and post mortem
SR reflection topography was applied to study the interaction of slip dislocations with the grain boundaries in Fe-4at%Si bicrystals deformed by compression. Three experimental settings with either a white or monochromatic beam were used and the corresponding orientation contrast analysed. Dislocation transmission through the grain boundary was observed in bicrystals with favourable geometry of the slip systems.