The invention discloses a light-weight high-strength Ni-Co-based single-
crystal high-entropy
alloy and a preparation method thereof, the single-
crystal high-entropy
alloy comprises the following chemical components in percentage by atom: 45-55 at% of Ni, 15-20 at% of Co, 9-12 at% of Cr, 9-12 at% of Al, 4-8 at% of Ti, 1-2 at% of Mo, 0-1 at% of W and 0-0.1 at% of Hf, and the single-
crystal high-entropy
alloy comprises the following eight elements: 45-55 at% of Ni, 15-20 at% of Co, 9-12 at% of Cr, 9-12 at% of Al, 4-8 at% of Ti, 1-2 at% of Mo, 0-1 at% of W and 0-0.1 at% of Hf. The preparation method comprises the following steps: obtaining a
liquidus temperature through analog calculation, and obtaining an eutectic
dissolution temperature through a
melting point test; the preparation method comprises the following steps: putting elemental elements Ni, Co, Cr, Ti, Mo and W into a
crucible of a
vacuum induction melting furnace in sequence, and pouring into a master alloy
ingot; a high-speed solidification Bridgeman method and a
seed crystal method are adopted to prepare a crystal grain with the orientation of 1t; 001gt, 001gt; preparing a single-crystal high-entropy alloy test bar; and the single-crystal high-entropy alloy test bar is sequentially subjected to
solution treatment, first-stage aging and second-stage aging, and the light-weight high-strength Ni-Co-based single-crystal high-entropy alloy is obtained. The single-crystal high-entropy alloy prepared through the method is small in density and meanwhile has excellent room-temperature
mechanical property and high-temperature
mechanical property.