Mechanical properties of a 316L/T91 weld joint tested in lead–bismuth liquid

The mechanical strength of T91/316L weld joint assembled by electron beam process is investigated in air and in a liquid lead bismuth bath at 300 and 380 °C using the small punch test. It is shown that the mechanical response in air of the weld joint is similar to that of the T91 base material. The plastic deformation is mainly concentrated in the T91 part of the weld joint which promotes cracking in this material. Testing in liquid lead bismuth bath results in a reduction in ductility and the formation of brittle cracks. The T91/weld interface is found to be rather resistant as it cracks late in the test and after a large crack propagated in the T91 steel.