Nanometer precipitated phase reinforced ultra-fine grain high-strength steel and preparation method thereof

The invention discloses nano precipitated phase reinforced ultra-fine grain high-strength steel which comprises the following chemical components in percentage by atom: 24-28% of Ni, 4-7% of Al, 1-5% of Ti, 0-2% of C, 0-2% of Cr, 0-2% of Mo, 0-2% of W, Cr + Mo + W: lt and the balance of Fe and inevitable impurities. 5%, with the balance being iron and inevitable impurities. After the high-strength steel is subjected to heat treatment, a nano precipitation strengthening phase Ni3 (Al, Ti) of an L12 structure is separated out and is uniformly and dispersedly distributed in the high-strength steel, the volume fraction is 30% or above, the size is 10-100 nm, and the high-strength steel with high strength and high toughness at the low temperature ranging from 500 DEG C is obtained. The high-strength steel does not contain precious elements and can contain a small amount of carbon elements, high-purity iron raw materials do not need to be used, and the cost is low. And the cost is low. 本发明公开了一种纳米沉淀相强化的超细晶高强钢，以原子百分比