Method for laser cladding and forming of metal or alloy under partial atmosphere protection

A method for laser cladding and forming of a metal or alloy under partial atmosphere protection, comprising:

• providing a metal or alloy powder beam by an inert carrier gas and a focused laser beam;
• moving the metal or alloy powder beam with the inert carrier gas and the focused laser beam on a machined surface;
• and
• forming at least two layers of inert protective gas laminar flow gas curtain at an outer periphery of the metal or alloy powder beam to isolate external gas,
• wherein the metal or alloy powder beam and the inert carrier gas are coaxial with the focused laser beam, and spraying directions thereof are consistent;
• and
• wherein the method is performed by using a coaxial spray head, which comprises
• a metal or alloy powder beam passage arranged axially at a center of the coaxial spray head, for transporting the metal or alloy powder beam;
• laser beam passages arranged symmetrically at an outer periphery of the metal or alloy powder beam passage, for transporting the focused laser beam;
• first inert protective gas passages arranged symmetrically at an outer periphery of the laser beam passages, for transporting a first layer of the at least two layers of inert protective gas laminar flow gas curtain;
• and
• second inert protective gas passages arranged symmetrically between the metal or alloy powder beam passage and the laser beam passages, for transporting a second layer of the at least two layers of inert protective gas laminar flow gas curtain.