Mini-Tensile Experiments of Clock-Rolled Zirconium Plate

We present our efforts to measure the tensile strength of clock-rolled pure zirconium in the through-thickness (TT) direction of the plate. Although the plate is too thin to produce standard ASTM tensile samples in the TT orientation, such measurements are relevant to benchmarking our constitutive models of hardening and texture evolution. We have designed a fixture and sample to perform tensile tests on our 9 mm thick plate. The sample is a double-ligament mini-tensile sample: 8 × 8 × 1 mm overall; each ligament has a gage section of 1 × 1 × 3 mm. In contrast, our standard “macro” tensile sample is a flat dogbone with a gage section of 3 × 1.5 × 25 mm. We validate our design by comparing the results of mechanical tests performed on samples of both geometries. Although the hardening response is nearly identical, the flow stress of the miniature samples is offset by +25 MPa at the onset of plastic yield. We present our efforts to resolve the origin of this offset.