Rejuvenation-to-Relaxation Transition Induced by Elastostatic Compression and Its Effect on Deformation Behavior in a Zr-Based Bulk Metallic Glass

Jingxian Cui,Siyi Di,Zhengguo Zhang,Baolong Shen,Qiang Luo

doi:10.3390/met12020282

Jingxian Cui, Siyi Di + Show 3 more

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https://doi.org/10.3390/met12020282

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Abstract

The effect of uniaxial elastostatic compression on the deformation behavior of the Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit1) bulk metallic glass (BMG) was reported. The as-cast alloy was pre-compressed under various time (20, 40 and 60 h) at a preloading level of 87% of its yield strength. It was found that elastostatic compression can lead to structural rejuvenation or relaxation depending on the pre-compression time. Elastostatic compression, for 40 h, increased the free volume and improved the plasticity of the BMGs from 1.4% to 3.4%, but preloading for 60 h decreased the free volume and worsened the plasticity. In addition, the heterogeneous structure evolution during creep deformation has been analyzed by the Maxwell-Voigt model with two Kelvin units, revealing that more (less) defects with larger size are activated after elastostatic compression treatment for 40 h (60 h). This work sheds new light on the correlation between heterogeneous structure and plasticity/creep behaviors of Zr-based BMGs.

Highlights

Cooling a glass-forming metallic liquid to room temperature results in a metallic glass.Compared with traditional alloys, bulk metallic glasses (BMGs) are fascinating structural and functional materials which attract considerable attention all over the world, owing to their outstanding magnetic, chemical and mechanical properties, such as excellent soft magnetic properties, high strength, large elastic limit and high Young’s modulus [1,2,3,4]
Applying the elastostatic compression for 20 and 40 h led to the increase of plasticity to 2.1% and 3.4%, respectively
Despite the plasticity varies with different elastostatic compression durations, all the AC and pre-compression treated samples have the similar strength of the AC sample, which is consistent with the former report [32]

Summary

Introduction

Bulk metallic glasses (BMGs) are fascinating structural and functional materials which attract considerable attention all over the world, owing to their outstanding magnetic, chemical and mechanical properties, such as excellent soft magnetic properties, high strength, large elastic limit and high Young’s modulus [1,2,3,4]. Their poor plasticity at room temperature severely restricts the structural application [5]. To improve the plasticity of BMGs at room temperature, three types of general strategies have been developed as follows: 1. modifying compositions of BMGs; 2. producing composite structure that comprises amorphous matrix and second phase particles or dendrites [9,10,11]; 3. introducing structural heterogeneity in BMGs [12,13]

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