Surface slip deformation characteristics for perforated Ni-based single crystal thin plates with square and triangular penetration patterns.

The surface slip deformation characteristics around two different patterns of film cooling holes in perforated plates were investigated by room-temperature tensile testing. An ARAMIS system was employed to observe the strain distribution on the sample surface. The development of slip traces and the microstructure after fracture of the specimens were analyzed by optical microscope (OM) and scanning electron microscopy (SEM), respectively. The maximum surface strain of the specimens with a triangular penetration pattern measured by the ARAMIS system was found to be larger than that of the perforated square-patterned specimens at both the yield point and when approaching fracture. However, specimens with a triangular penetration pattern have a greater yield strength and ultimate tensile strength than the specimens with a square penetration pattern because the cross-cleavage fracture of the specimen with the square penetration pattern leads to larger damage than the single-slip deformation fracture of the specimen with the triangular penetration pattern. Octahedral slip systems of the two kinds of specimens were activated in the same slip system, and the slip band observed in the experiment is consistent with crystal plasticity theory. [ABSTRACT FROM AUTHOR]