Achieving a remarkable low-temperature tensile ductility in a high-strength tungsten alloy

Hot-swaging yields a high ultimate tensile strength of 712 MPa but a limited tensile ductility with the total elongation of 3.6% at a testing temperature of 200 degrees C in a representative W-0.5wt.%ZrC alloy. In this work, the evolution of Vickers micro-hardness with annealing temperatures is investigated in detail, which contributes to a rough index chart to guide the search for an optimized post-annealing temperature. Through the post-annealing around 1300 degrees C, an outstanding tensile ductility at 200 degrees C, including a uniform elongation of 14% and a total elongation of similar to 25%, has been achieved without the sacrifice of its strength. The evolution of dislocations and grain structures with the annealing temperatures accessed through backscattered scanning electron microscope and transmission electron microscope analysis reveals that the improved low-temperature tensile ductility has resulted from the reduction of residual dislocations and dislocation tanglement via the static recovery, which provides more room to accommodate dislocations, and hence stronger strain hardening ability and tensile ductility.