Microstructure and mechanical properties of micro laser welding NiTiNb/Ti6Al4V dissimilar alloys lap joints with nickel interlayer

The micro laser lap welding method formed a lap joint of NiTiNb shape memory alloys (SMAs) to Ti6Al4V alloy with a Ni interlayer. The microstructure and mechanical properties in the lap weld were studied by Optical microscope (OM), Scanning electron microscope (SEM), Energy dispersive spectroscopy (EDS), and tensile tests. The results show that the addition of a Ni interlayer still formed the brittle intermetallic compound Ti2Ni. Moreover, the width of the brittle intermetallic compound Ti2Ni region can reduce the crack sensitivity of the lap joint. The lap joint fractured in the fusion zone on the Ti6Al4V alloy side with a maximum shear load of 122N.

Automated summary

The micro laser lap welding method was used to form a lap joint between NiTiNb shape memory alloys and Ti6Al4V alloy with a Ni interlayer, resulting in the formation of the brittle intermetallic compound Ti2Ni. Despite the addition of the Ni interlayer, the lap joint still fractured in the fusion zone on the Ti6Al4V alloy side, with a maximum shear load of 122N.