Statistical study of ductility-dip cracking induced plastic deformation in polycrystalline laser 3D printed Ni-based superalloy.

摘要: Ductility-dip cracking in Ni-based superalloy, resulting from heat treatment, is known to cause disastrous failure, but its mechanism still not completely clear. A statistical study of the behavior as a function crystal orientation laser 3D-printed DL125L superalloy polycrystal investigated here using synchrotron X-ray microdiffraction. The dislocation slip system each forty grains adjacent 300 μm long crack has been analyzed through Laue diffraction peak shapes. In all these grains, edge-type geometrically necessary dislocations (GNDs) dominate, and their line directions are almost parallel plane. Based on Schmid’s law, equivalent uniaxial tensile force direction revealed normal trace crack. qualitative thus proposed. Thermal stress perpendicular scanning elevated due significant temperature gradient, locations materials where thermal exceeds yield undergo plastic deformation mediated by GND activations. As inside pile up at grain boundaries, local strain/stress keeps increasing, until regions fail sustain further deformation, leading voids formation cracks propagation.