Experimental investigations on the 3D deformation of the nucleation process of PLC shearing band in Al-Cu alloy
Al-Cu合金中PLC剪切带成核过程三维变形的实验研究

The 3D deformation process of type-B PLC shearing band inAl-Cu alloy is captured by the help of a high speed digital photography with 1000 frames per second. A technique based on a novel high-speed digital speckle pattern metrology consisting of in-plane and out-of-plane deformation measurement methods is used for obtaining the playback of the 3D deformation process. The result shows one of the nucleation methods of type-B band: the shearing band initiates at a lateral specimen surface as a narrow band at an angle of 53 to the tensile axils and shears along the thickness direction. Subsequently the band front begins to propagate to the other lateral specimen surface along its length direction and expands in its width direction accompanying with the drop of the stress. When the front of the band reaches the other lateral surface, the band begins to expand in its width direction instantly and avalanchine shearing deformation happens. Based on the out-of-plane data, the relationship to the nucleation positions of following bands is that the latter one initiates on the front edge of the former one and the spacing of their center lines is half of the band width.