Research on the dynamic plasticity mechanism of additive manufactured nickel-chromium-molybdenum corrosion-resistant alloy steel under impact load

ZP Hao and JC Hu and YH Fan and LJ Li and LH Kong, ENGINEERING FAILURE ANALYSIS, 152, 107503 (2023).

DOI: 10.1016/j.engfailanal.2023.107503

In this paper, the dynamic mechanical response and microstructure evolution of 022Cr17Ni12Mo2 alloy steel under different impact velocities were studied at the atomic scale by Split Hopkinson pressure bar (SHPB) tests combined with molecular dynamics simulation, and the microstructure was characterized by TEM, HRTEM and EBSD. The results show that when the impact velocity (Up) is greater than 0.5 km/s, plastic waves appear in the material. The main reason for plastic deformation is that the impact load exceeds the Huguenot elastic limit of the material. At this time, the deformation of the microstructure is controlled by the nucleation and slip of dislocations. When the impact velocity is greater than 0.75 km/s, both elastic waves and plastic waves exist at the same time, and more dislocation junctions and L-C locks begin to appear. The movement of dislocations is restricted, and the plasticity decreases. When the impact velocity is greater than 1.5 km/s, due to the sharp increase of shear stress, more slip systems are activated, dislocations multiply, and plasticity is enhanced. Because the distribution of Mo element makes the grain boundary more stable, it affects the plastic deformation of the material. This work has important guiding significance for the in-depth understanding of the enhancement and failure mechanism of 022Cr17Ni12Mo2 alloy steel under impact load.

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