Investigating the influence mechanism of Mo content on solid solution and grain boundary strengthening in NiCoMo alloys using molecular dynamics

This study systematically investigates the effects of varying molybdenum (Mo) content on the solid solution strengthening and grain boundary strengthening mechanisms in NiCoMo alloys using molecular dynamics (MD) simulations. Through comparative analyses of dislocation evolution, stress distribution, and phase transformation behavior, the critical role of Mo in enhancing the mechanical properties of the material is revealed. The results indicate that: In solid solution strengthening, at a Mo content of 12% (NiCoMo12), lattice distortion effectively inhibits dislocation slip, significantly improving the matrix strength. For grain boundary strengthening, at a Mo content of 30% (GB-30), the pinning effect of grain boundaries is markedly enhanced, with the most uniform local stress distribution and the smallest shear strain regions, demonstrating optimal strengthening performance. Additionally, increasing Mo content accelerates the FCC → HCP phase transformation, but an appropriate Mo concentration effectively suppresses this transformation, maintaining the stability of the crystal structure. The synergistic effects of solid solution strengthening and grain boundary strengthening achieve dual improvements in material strength and stability. This work provides theoretical support for the design and optimization of NiCoMo alloys.