Anti-cavitation damping composite metal structure for flow passage component

An anti-cavitation damping composite metal structure for a flow passage component, formed by cladding, layer by layer, a gradient material on a substrate of the flow passage component;

• and forming a plurality of periodic structures on a surface of each layer of the gradient material through etching by an ultrafast laser to absorb a part of an impact load energy caused by a cavitation of the flow passage component, wherein the each layer of the gradient material together forms a gradient coating with a toughness increasing layer by layer and a hardness decreasing layer by layer from outside to inside;
• wherein the preparation method comprises the following steps:
• step S1:
• polishing a substrate made of high-manganese aluminum bronze, and forming first periodic structures of the plurality of periodic structures on the substrate made of the high-manganese aluminum bronze through the etching by a picosecond green laser, wherein a spacing between the first periodic structures is an integer multiple of a wavelength of a stress wave applied onto the corresponding surface of the flow passage component;
• step S2:
• laser cladding a nickel copper layer by coaxial powder feeding using a semiconductor laser on a surface of the substrate made of the high-manganese aluminum bronze, polishing the nickel copper layer, and forming second periodic structures of the plurality of periodic structures on the nickel copper layer through the etching by the picosecond green laser, wherein a spacing between the second periodic structures is an integer multiple of a wavelength of a stress wave applied onto the corresponding surface of the flow passage component;
• step S3:
• laser cladding a hard alloy layer on a surface of the nickel copper layer by coaxial powder feeding using the semiconductor laser, polishing the hard alloy layer, and forming third periodic structures of the plurality of periodic structures on the hard alloy layer through the etching by the picosecond green laser, wherein a spacing between the third periodic structures is an integer multiple of a wavelength of a stress wave applied onto the corresponding surface of the flow passage component;
• and
• step S4:
• laser cladding a ceramic alloy layer on a surface of the hard alloy layer by coaxial powder feeding using the semiconductor laser to form a gradient damping composite coating.