Strain-Rate Dependence of Tensile Behavior in Commercial-Grade Tungsten-Effect of Recrystallization Condition

Abstract

The tensile deformation behavior of double-forged (DF-W) and recrystallized (RX-W) commercial-grade tungsten was investigated at 700 degrees C. With increasing strain rate, the dominant dynamic recrystallization (DRX) mechanism changes from continuous dynamic recrystallization (CDRX) to discontinuous dynamic recrystallization (DDRX). For DF-W, pre-existing sub-grains promote CDRX and associated a high-DRX fraction, resulting in reduced post-necking strain under a static condition. With increasing strain rate, a shift in the restoration mechanism from CDRX to DDRX contributes to the enhanced ductility in DF-W, while RX-W shows enhanced flow hardening without a loss of ductility. These results suggest that the strain-rate dependence of mechanical behavior depends on the initial microstructure.