Tensile properties and deformation mechanisms of Re-0.1ZrO₂ at room temperature and ultra high temperatures

Tensile properties and deformation mechanisms of Re-0.1ZrO₂ at room temperature and 1700–2000 °C were investigated. The microstructure and fracture morphology were observed by a scanning electron microscope, a focused ion beam-scanning electron microscope and a transmission electron microscope. The experimental results shows that both tensile strength and elongation of Re-0.1ZrO₂ decrease at high temperatures compared to those at room temperature. At room temperature, the Re-0.1ZrO₂ exhibits a mixed fracture mode of intergranular fracture and intragranular secondary plastic fracture. The deformation is accommodated by twinning and dislocation motion. Large number of {112¯1}<1¯1¯26 > tension twins nucleate and the activated primary dislocation slip system is pyramidal <c + a > dislocation slip. In the temperature range of 1700–2000 °C, the alloy is characteristics of intergranular fracture. The twinning is completely suppressed and the deformation of Re-0.1ZrO₂ is dominated by movement of dislocations, whose main slip system remains pyramidal slip, with <a > type dislocation slip activated. Meanwhile, dislocation cross-slip and climb are also activated.