Laser joining of Mo and Ta sheets with Ti6Al4V or Ni filler

• Published in: Optics and laser technology 2018-10, Vol.106, p.487-494
• Main Authors: Zhou, Xingwen, Huang, Yongde, Chen, Yuhua, Peng, Peng
• Format: Article
• Language: English
• Subjects: Base metal; Dissimilar laser joining; Dissimilar metals; Filler metal; Filler metals; Interface; Intermetallic compounds; Joining; Laser beam welding; Melting points; Microwaves; Molybdenum; Nickel; Refractory metals; Tantalum; Tensile strength; Titanium base alloys
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2018.05.004

[Display omitted] •Dissimilar laser joining of Mo and Ta with Ni or Ti6Al4V filler was performed.•The role of filler metals on the microstructure and mechanical properties of joints was investigated.•The formation of two different interfaces in each joint would affect the mechanical properties. Joining of Mo to Ta is important in manufacturing of high temperature microwave device. However, it is difficult to weld these two refractory metals directly because of their limited weldability. This study presents a laser joining method of Mo and Ta using Ti6Al4V or Ni as filler metal to prevent the mixture of two base metals in molten pool. The bulk of the Mo and Ta remained solid and joined by the liquid filler metal since the melting point of filler metal is considerably lower than that of base metals, resulting in two interfaces formed in each joint. The tensile strength of the Mo/Ni/Ta joint fractured from Ni/Ta interface is 19% lower than that of Mo/Ti6Al4V/Ta joint broken at base metal of Ta due to the formation of IMCs. These results offer a reference to filler metals selection for the joining of Mo to Ta, and highlight a possible method when dissimilar joining of two hard-to-weld metals especially refractory metals.