Properties at elevated temperature and recrystallization of molybdenum doped with potassium, silicon and aluminum

Potassium, silicon and aluminum (AKS) were doped in molybdenum by solid–liquid mixing, drying, and reducing. Rods and wires were prepared by pressing, sintering, swaging and drawing. Ten-millimeter diameter as-swaged rods were subjected to mechanical measurement. Their tensile properties at 973, 1273 and 1623 K were investigated and compared with that of undoped samples. The ultimate tensile strength (σb) and yield strength (σs) were increased by dopants at 973 K and 1273 K while necking area (ψ) and elongation (δ) were decreased. However, all of the strength and ductility properties were increased at 1623 K when compared with the undoped samples. Strength and ductility properties dropped simultaneously at 1623 K as compared with those at lower temperatures. Correspondingly, fractography analysis on pure molybdenum rods indicated that the breaking path varied from intragranular to intergranular. Primary and secondary recrystallization temperatures were determined by differential scanning calorimetry (DSC) to be 1655 and 1746 K respectively. Furthermore, some dopant particles containing potassium, silicon, and aluminum were detected by SEM and EDX in as-drawn wires of 1 mm diameter.