Mechanical Behavior at the Nanoscale VI: Poster Session
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS Structural Materials Division, TMS: Computational Materials Science and Engineering Committee, TMS: Mechanical Behavior of Materials Committee, TMS: Nanomechanical Materials Behavior Committee
Program Organizers: Matthew Daly, University of Illinois-Chicago; Douglas Stauffer, Bruker Nano Surfaces & Metrology; Wei Gao, University of Texas at San Antonio; Changhong Cao, McGill University; Mohsen Asle Zaeem, Colorado School of Mines
Monday 5:30 PM
February 28, 2022
Room: Exhibit Hall C
Location: Anaheim Convention Center
H-12: Atomistic Modeling of the Mechanical Behavior of Gradient Nanoglasses: Suyue Yuan1; Paulo Branicio1; 1USC
A severe weakness of Metallic glasses (MGs) is their lack of ductility and tendency of catastrophic failure by shear banding. With the introduction of a nanoscale grain structure, named nanoglasses (NGs), the ductility of MGs can be significantly increased. A promising new design to compromise strength and ductility in NGs is based on the generation of a gradient distribution of grain sizes creating a so-called gradient nanoglass (GNG). Here, we use large-scale molecular dynamics simulations to investigate the deformation and failure mechanisms of GNGs. Simulations of tensile and compressive loading and nanoindentation of GNGs with grain sizes from 3 to 15 nm reveal a contrasting and unexpected behavior for loading perpendicular and parallel to the gradient direction. Overall, the gradient distribution of grain sizes promotes delocalization of the plastic deformation and delays failure by arresting the propagation of critical shear bands enhancing the observed overall ductility.
H-13: Dynamic Mechanical Properties of High-entropy Alloys: Aomin Huang1; 1Univerisity of California San Diego
Multi-principal elements alloys with more than five components, namely high-entropy alloys (HEAs) have been extensively studied due to their excellent mechanical properties as promising structural materials. As novel alloys, excellent performances such as high strength at both cryogenic and high-temperature conditions, great resistance toward classic strength-ductility trade off, have been found in recent studies. However, most emphases have been placed to study their mechanical properties subjected to low strain-rate which leads to insufficient understanding of their properties at high strain-rate condition. In the present study, compression tests with varying strain rates and temperatures are performed on split-Hopkinson pressure bar (SHPB) system to establish their microstructure evolution and deformation mechanisms. Here, we report on a novel method to improve dynamic properties by introducing multiple strengthening mechanisms such as microband, martensitic transformation, and forest hardening.