Diffusion bonding of TiAl using Ni/Al multilayers

Recrystallization Behavior at Diffusion Bonding Interface of High Nb Containing TiAl Alloy

“…He et al achieved a sound joint with lower bonding parameters by using hydrogenated Ti-6Al-4V interlayer to optimize the interface contact and facilitate the elements diffusion. [10,11] Simões et al [12][13][14][15] carried out the diffusion bonding of TiAl alloy by using nano-scaled Ni/Al as interlayer and the bonding temperature was reduced to 900 C without decreasing the bonding strength. Except for Ni/Al nanolayers, the Ti/Al foil [16][17][18] was also applied as an intermediate element to produce sound joints of g-TiAl-based alloys.…”

Anisothermal solid-state reactions of Ni/Al nanometric multilayers

“…Reactive multilayers by themselves could also be used for joining purposes mainly by taking advantage of their increased diffusivity and reactivity due to their nanometric dimensions. In the reaction assisted diffusion bonding process the reactive multilayers are directly deposited onto the materials being joined and promising results have been achieved [10,11]. In fact, the use of reactive multilayers could be very interesting for joining advanced materials, like intermetallics (TiAl) and superalloys (Inconel).…”

Shear Strength of Reactive Resistance Welded Ti6Al4V Parts with the Use of Ni(V)/Al Multilayers

“…All of it indicates a quasi-brittle cracking mode, bearing also features of some plastic deformation. The observations carried out by Simoes et al [10] for diffusion bonded TiAl alloys revealed that the joint characterized by a strength of~300 MPa cracked in similar way, except for the lack of the network of perpendicular cracks, which is specific for Ni(V)/Al multilayers reacted by SHS. The results obtained for other methods of joining of Ti6Al4V alloys like laser beam welding with niobium interlayer revealed fully brittle cracking during shear tests being a consequence of hydrogen and oxygen contamination of weld pool.…”

“…[9] On the other hand, diffusion bonding of TiAl alloys with the Ni(V)/Al multilayers reaction proceeded through solid state diffusion. [10,11] This process, carried out in vacuum furnace, results in uniform heating of all components to be joined. However, the heat of exothermic reaction of Ni(V)/Al multilayers is practically lost due to long processing time.…”

“…However, diffusion bonding of titanium alloys using Ni/Al multilayers indicates that shear strength higher than 300 MPa is achievable only when the processing time is relatively long (> 60 minutes). [10] It indicates that the RRW process has an advantage in time-temperature scale over the currently applied methods of materials joining with the use of reactive Ni/Al multilayers. The knowledge of crack propagation path and the characteristic features of fractured surfaces in the joint usually help both to classify the formed connections as well as to improve their strength.…”