NiTiHf high temperature shape memory alloy with two-way shape memory effect, and 4D printing method and application thereof

A 4D printing method of NiTiHf high temperature shape memory alloy comprising:

• (1) powder processing:
• preparing and vacuum smelting high-purity titanium, high-purity nickel and high-purity crystalline hafnium according to a selected atomic percentage to obtain NiTiHf alloy rods, preparing NiTiHf alloy powder by an electrode induction-melting gas atomization method or a plasma rotating electrode atomization method, and sieving to obtain NiTiHf alloy powder with a selected size range;
• (2) constructing a model and preheating a substrate:
• building a three-dimensional model of structural parts to be prepared, completing a slicing process and generating a print file;
• the substrate is a NiTi alloy substrate and preheating the NiTi alloy substrate;
• (3) forming by 4D printing:
• forming a NiTiHf high temperature shape memory alloy with a two-way shape memory effect by utilizing the NiTiHf alloy powder sieved in step (1) through a laser powder bed fusion 4D printing additive manufacturing with a laser power of 45 to 100 W and a scanning speed of 100 to 200 mm/s, or by an electron beam powder bed fusion 4D printing additive manufacturing with a substrate preheat temperature of 300 to 500° C.;
• wherein in step (3), a size of NiTiHf alloy powder suitable for the electron beam powder bed fusion 4D printing additive manufacturing is 50 to 120 m.