We elucidate here the deformation mechanisms and underlying reasons that contributed to high ductility (10.2%) and high static toughness (112.5 MJ m⁻³) in an ultrahigh strength (1860 MPa) cobalt-free 19Ni3Mo1.5Ti maraging steel characterized by high density (2.3 × 10²⁴ m⁻³) of η-Ni₃(Ti,Mo) and B2-Ni(Mo,Fe) nanoscale precipitates with low lattice misfit of ＜1% with the martensite matrix. Multiple deformation processes occurred during plastic deformation. Lath-morphology of martensite was dramatically segmented with angles of 30°, 60° or 120° with large pile-up of dislocations at the segmented boundaries. This occurred because of the interactive ability of edge and screw dislocations along the martensite habit planes, which led to kinks and jogs. The low lattice misfit (0.6% ~ 0.9%) precipitates interacted with dislocations leaving stacking fault ribbons within precipitates that build a large long range of back stress producing a high strain-hardening response. Additionally, nanoscale twinning occurred. The above contributions to ductility are envisaged to be in addition to the significantly reduced elastic interaction between the low lattice misfit nanoscale precipitates and dislocations that reduces the ability for crack initiation at the particle-matrix interface.

我们在此阐明了变形机理和导致高延展性（10.2％）和高静态韧性（112.5 MJ m ^-3）的变形机理和根本原因，这些超高强度是在高强度（1860 MPa）无钴的19Ni3Mo1.5Ti马氏体时效钢中，其高密度（ 2.3×10 ²⁴米^-3）的η-Ni系₃（Ti，Mo）和B2-Ni（Mo，Fe）纳米级析出物，其与马氏体基体的晶格失配低至＜1％。塑性变形过程中发生了多个变形过程。马氏体的板条形貌以30°，60°或120°的角度显着地分割，在分割的边界处有大量的位错堆积。发生这种情况是由于沿马氏体惯性平面的刃和螺钉错位的相互作用能力，导致了扭结和慢跑。低晶格失配（0.6％〜0.9％）的析出物与位错相互作用，在这些析出物中堆积断层带，从而形成很大范围的背应力，产生高应变硬化响应。另外，发生了纳米级孪晶。