Understanding Deformation Behavior in Sintered Fe36Ni Alloy Through Nanoindentation Experiments and Molecular Dynamics Simulation

SK Sahni and S Bhowmick and A Upadhyaya, ADVANCED ENGINEERING MATERIALS (2023).

DOI: 10.1002/adem.202301460

In this work, the nanoindentation-induced deformation behavior in sintered Fe36Ni is investigated using experiments and molecular dynamics simulations. The Fe36Ni alloy is synthesized through the powder metallurgy route. A microstructural study of the sintered sample reveals the formation of both hard alpha-(Fe, Ni) and soft gamma-(Ni, Fe) phases due to compositional inhomogeneity, and increasing the sintering temperature enhances the gamma-(Ni, Fe) phase formation. The experimentally measured nanoindentation features are correlated to atomistic origin using molecular dynamics simulation. Deformation behavior is explored using local shear strain and atomic displacement plot, and a detailed investigation of various dislocation nucleation and their interaction is performed to gain insights into the mechanisms governing plastic deformation. The plastic deformation of alpha-(Fe, Ni) phase is governed by dislocation with Burger's vector b = (1/2) <111> and b = <100> whereas, sessile dislocations such as Stair-rod (b = 1/6 <110>), Frank (b = 1/3 <111>), and Hirth lock (b = 1/3 <100>) are found to be responsible for the plastic deformation and also contribute in strain hardening of gamma-(Ni, Fe) phase.

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