Method of joining different metal materials by friction welding

摘要

A rod material (6) made of Ti alloy has a larger diameter portion (6b) at the end, which is joined with the end (7a) of material (7) made of Ti-Al intermetallic compound, by friction welding, to form a poppet valve for an internal combustion engine. Instead of providing such larger diameter portion (6b), the end (7a) of the material made of Ti-Al intermetallic compound may be heated to facilitate joining.