Development of the bubble structure from selectively deforming potassium-pores in doped tungsten wires

Abstract

As the AKS-doped sintered ingot is processed into wire, the smaller potassium-containing pores appear to be less deformable than the larger ones. In the present work the consequences of this selective pore deformation were investigated on the characteristics of the developing bubble dispersion in different heat-treated samples. The results indicated that the refinement of the potassium distribution during thermomechanical processing occurs more effectively if the potassium in the sintered ingot is enclosed in relatively large pores. It was concluded from a simple estimation that the size-dependent deformation of the potassium-pores exerts an equalizing effect on the potassium distribution manifesting itself in the fact that an initial broad size distribution of potassium-pores in the sintered ingot will be moderated during thermomechanical processing to a relatively narrow size distribution of the bubbles in the wire. In light of the size-dependent pore deformation, the occurrence of the isolated single bubbles in AKS-doped tungsten wires was also briefly discussed.