Molecular Dynamics Simulation Study of Uniaxial Ratcheting Behaviors for Ultrafine-Grained Nanocrystalline Nickel

Journal Article · Thu Aug 15 04:00:00 EDT 2019 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-019-04256-Z· OSTI ID:22970533

Pal, Snehanshu; Gururaj, Karanam; Meraj, Md. ^[1]; Bharadwaj, Ravindra Giriraj ^[2]

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1. National Institute of Technology Rourkela, Department of Metallurgical and Materials Engineering (India)
2. University of California Riverside, Department of Mechanical Engineering (United States)

In this paper, molecular dynamics (MD) simulation-based study of deformation behavior of ultrafine-grained nanocrystalline nickel under asymmetric cyclic loading having stress ratios (R) such as − 0.2, − 0.4 and − 0.6 for different temperatures, viz. 100, 300 and 500 K, has been performed using embedded atom method potential. The predicted ratcheting strain by MD simulation for nanocrystalline Ni varies from 15 to 30%. A significant increase in ratcheting strain has been observed with the increase in temperature. It has been observed that the number of vacancies increases, and the number of clusters decreases with the increase in temperature. Slight reduction in crystallinity is identified at the middle of the each loading cycle from the performed cluster analysis. Zigzag pattern of dislocation density has been observed and leads to the decrease in dislocation density with the increase in temperature. Stress ratio does not show any significant effect on the number of vacancies, clusters and dislocation density on structural evolution during the asymmetric cyclic loading. Slight change in the grain rotation has been observed with the increase in temperature, and there is almost no change in the final texture evolved. From the post-tensile tests, ultimate tensile strength that remains same may be due to constant average dislocation density.

• OSTI ID: 22970533
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 8 Vol. 28; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CLUSTER ANALYSIS
CRYSTALS
DISLOCATIONS
MOLECULAR DYNAMICS METHOD
NANOSTRUCTURES
NICKEL
RATCHETING
SIMULATION
STRESSES
TENSILE PROPERTIES