Publications Details
Weldability and weld doping of commercial purity molybdenum
The GTA weldability and fracture behavior of low and high carbon arc cast and powder metallurgy molybdenum has been examined. Defect-free welds were produced in the arc cast grades. For the PM grade, however, severe centerline cracking and large scale porosity were encountered. The center-line cracking and pore formation were found to result from the dissolution of oxygen-bearing inclusions present in the starting material. Moreover, titanium or hafnium additions, incorporated into the weld by RF sputter coating the joints prior to welding, had several beneficial effects. These were reductions in the centerline cracking and pore formation in the PM welds, hardening of the weld fusion zone, and a reduction in the tendency for intergranular failure in the fusion zone for all base materials. The mechanisms by which dopant additions improve the welding and fracture behavior is also discussed. 22 refs., 16 figs., 2 tabs.