High-plasticity Fe-Mn-Co-Cr-Si metastable high-entropy alloy and preparation method thereof

The invention discloses a high-plasticity Fe-Mn-Co-Cr-Si metastable high-entropy alloy and a direct energy deposition technology forming method, and belongs to the field of high-entropy alloys. The metastable high-entropy alloy is of an FCC single phase, the chemical formula of the metastable high-entropy alloy is FeaMnbCocCrcSid, the atomic percent a is 35-45, the atomic percent b is 30-40, the atomic percent c is 8-10, the atomic percent d is 0.5-6, and the sum of a, b, 2c and d is 100. The preparation method comprises the steps that pre-alloyed powder serves as a raw material, a product is obtained through an additive manufacturing process, and during additive manufacturing, the laser spot diameter is controlled to be 1-2.5 mm, the substrate preheating temperature is 100-150 DEG C, the shielding gas flow is 7-15 L/min, the laser power is 100-500 W, the laser scanning speed is 4-10 mm/s, the single-channel lap joint amount is 25-50%, and the Z-axis lifting amount is 0.4-0.55 mm. The process is simple, heat