Crack resistance of niobium alloy welded joints

Statical crack resistance of welded joints of thin-sheet niobium alloys VMTs and NTsU was analysed using the J-integral procedure. It is shown that welded joints have a tendency to the brittle failure. A decrease in running energy with the increase of welding speed from 2.8 to 16.6 mm/s results in the growth of the values of J-integral both for the weld metal and for the zone of thermal effect. The following thermal treatment under 1473 K during 1 h evokes a considerable growth of crack resistance of the both alloys compounds