Superior strain-hardening and strength-ductility synergy by hierarchical L12 phases in a highly (Al, Ti)-added medium-entropy alloy

Shiyu Du; Tuanwei Zhang; Jinyao Ma; Zhiming Jiao; Jianjun Wang; Shengguo Ma; Renlong Xiong; Zhihua Wang

Journal of Materials Research and Technology (Nov 2024)

Superior strain-hardening and strength-ductility synergy by hierarchical L12 phases in a highly (Al, Ti)-added medium-entropy alloy

Shiyu Du,
Tuanwei Zhang,
Jinyao Ma,
Zhiming Jiao,
Jianjun Wang,
Shengguo Ma,
Renlong Xiong,
Zhihua Wang

Affiliations

Shiyu Du: Institute of Applied Mechanics, College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan, 030024, China; Shanxi Key Laboratory of Material Strength and Structural Impact, Taiyuan University of Technology, Taiyuan 030024, China
Tuanwei Zhang: Institute of Applied Mechanics, College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan, 030024, China; Shanxi Key Laboratory of Material Strength and Structural Impact, Taiyuan University of Technology, Taiyuan 030024, China
Jinyao Ma: Institute of Applied Mechanics, College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan, 030024, China; Instrumental Analysis Center of Taiyuan University of Technology, Taiyuan 030024, China
Zhiming Jiao: Institute of Applied Mechanics, College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan, 030024, China; Shanxi Key Laboratory of Material Strength and Structural Impact, Taiyuan University of Technology, Taiyuan 030024, China
Jianjun Wang: Institute of Applied Mechanics, College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan, 030024, China; Shanxi Key Laboratory of Material Strength and Structural Impact, Taiyuan University of Technology, Taiyuan 030024, China
Shengguo Ma: Institute of Applied Mechanics, College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan, 030024, China; Shanxi Key Laboratory of Material Strength and Structural Impact, Taiyuan University of Technology, Taiyuan 030024, China
Renlong Xiong: Hubei Provincial Key Laboratory of Chemical Equipment Intensification and Intrinsic Safety, School of Mechanical and Electrical Engineering, Wuhan Institute of Technology, Wuhan 430205, China; Corresponding author.
Zhihua Wang: Institute of Applied Mechanics, College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan, 030024, China; Shanxi Key Laboratory of Material Strength and Structural Impact, Taiyuan University of Technology, Taiyuan 030024, China; Corresponding author. Institute of Applied Mechanics, College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.

Journal volume & issue: Vol. 33
pp. 2856 – 2867

Abstract

Read online

A novel precipitate-strengthened Co–Cr–Ni medium-entropy alloy with a pure “FCC + L12” dual-phase structure is developed by adding a high concentration (6 at.%) of Al and Ti elements. After aging heat treatment at 700 °C for 4 h, the hierarchical L12 phases, composed of primary large-sized L12 phases (∼70 nm) and secondary L12 particles (∼14 nm), are achieved. The designed alloy featuring hierarchical L12 phases exhibits excellent strength-ductility combinations and strain-hardening ability, properties that are much improved over their counterparts with homogeneous dispersed L12 phases (∼13 nm) and without L12 phases. Especially, the yield strength (1320 MPa), ultimate tensile strength (1886 MPa), and average strain-hardening rate (5.15 GPa) are obtained in the alloy with hierarchical L12 precipitates deformed at cryogenic temperature. The Orowan bypass mechanism of the primary L12 phases, along with the shearing mechanism of the secondary L12 phases, collectively contributes to the exceptional strength of the alloy with hierarchical L12 precipitates. The penetration of dislocations and stacking faults (SFs) in the primary L12 phases, combined with hetero-deformation-induced (HDI) hardening attributed to these hierarchical L12 precipitates, may be a key factor in improving strain-hardening properties of the alloy.

Published in Journal of Materials Research and Technology

ISSN: 2238-7854 (Print); 2214-0697 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Technology: Mining engineering. Metallurgy
Website: https://www.journals.elsevier.com/journal-of-materials-research-and-technology/

About the journal

Abstract

Keywords