A Heterogeneous Cantor Alloy with Ultrahigh Yield Strength under Extreme Loading

Area of Science:

• Materials Science
• Mechanical Engineering
• Metallurgy

Background:

• Cantor alloys offer excellent low-temperature fracture toughness.
• Their face-centered cubic structure limits yield strength for extreme environments.

Purpose of the Study:

• To enhance the dynamic yield strength of Cantor alloys for extreme environments.
• To investigate strengthening mechanisms in multilevel heterogeneous Cantor alloys.

Main Methods:

• Constructing multilevel heterogeneous structures in Cantor alloys.
• Testing dynamic yield strength at cryogenic temperatures and high strain rates (1800-2100 s⁻¹).
• Utilizing molecular dynamics simulations to analyze strengthening mechanisms.

Main Results:

• Achieved dynamic yield strength exceeding ~1.3 GPa at liquid nitrogen temperature.
• Identified contributions from dislocation, Hall-Petch, twin, and nanoscale planar defect strengthening.
• Observed significant strain hardening, indicating high energy absorption capacity.
• Molecular dynamics revealed nanotwins and 9R phases hinder dislocation slip and promote immobile stair-rod dislocations.

Conclusions:

• Multilevel heterogeneous structures significantly enhance Cantor alloy strength and strain hardening.
• The alloy demonstrates potential for applications in extreme environments requiring high strength and energy absorption.
• Nanotwins and 9R phases are critical for achieving superior mechanical properties.