LOW-TEMPERATURE DUCTILITY OF AN ELECTRON-BEAM-WELDED MOLYBDENUM SHEET PRE-DOPED WITH A SMALL AMOUNT OF CARBON

The mechanical properties of unwelded and electron-beam-welded sintered molybdenum sheets, in which carbon was doped or not, were examined by means of a tensile test at temperatures from -100 to 80°C. Scanning electron microscopy was applied to determine the fracture mode of the specimen and to observe the distribution of precipitates over grain boundaries. The results indicated that a small amount of pre-doped carbon was effective on the improvement in the low-temperature ductility of the welded specimen as well as that of the unwelded one. Such effects are reasonably explained in terms of the enhancement of the crack propagation stress in the fused zone of the weldment. © 1979.