Method of welding method, welding method and welded joint body

A design method of a welding method of welding a metal glass formed with a nano crystalline metal or an amorphous metal and a crystalline metal having a crystalline structure,

• wherein said welding method includes:
• applying energy to an interface where said metal glass and said crystalline metal make contact with each other or to said metal glass near the interface;
• heating and melting said metal glass to form a molten layer;
• and joining said metal glass to said crystalline metal, and said molten layer after said metal glass and said crystalline metal have been joined together has a glass formation ability, and
• wherein said design method designs a welding method by selecting a metal glass and a crystalline metal such that said metal glass has a glass formation ability in which a nose time of a TTT curve when a solid of said metal glass is reheated is 0.2 seconds or more, and said metal glass and crystalline metal satisfy a temperature range of a temperature of said metal glass at which a spread factor of said crystalline metal that has not been melted and said molten metal glass is 25% or more and a melting point of said crystalline metal to be 9.7% or more of a melting point of said metal glass, and
• wherein, in said welding method, a maximum temperature of said interface heated at the time of welding is 95% or less of the melting point of said crystalline metal.