Zhiming Li

Zhiming Li
Central South University | CSU ·  School of Materials Science and Engineering

PhD

About

160
Publications
100,857
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
7,290
Citations
Introduction
I am interested in the design-processing-microstructure-properties of bulk metallic materials as well as metallic and ceramic coatings.
Additional affiliations
August 2019 - July 2022
Max Planck Institute for Iron Research GmbH
Position
  • Guest Group Leader
September 2018 - present
Central South University
Position
  • Professor
January 2017 - July 2019
Max Planck Institute for Iron Research GmbH
Position
  • Group Leader
Education
September 2013 - September 2014
University of California, Davis
Field of study
  • Microstructure and mechanical behavior of SPD processed Ti alloys
May 2011 - December 2014
Shanghai Jiao Tong University
Field of study
  • Microstructural evolution and mechanical behavior of nanocrystalline materials
September 2008 - March 2011
Shanghai University of Engineering Science
Field of study
  • Metal and Ceramic Coatings

Publications

Publications (160)
Article
Metals have been mankind’s most essential materials for thousands of years; however, their use is affected by ecological and economical concerns. Alloys with higher strength and ductility could alleviate some of these concerns by reducing weight and improving energy efficiency. However, most metallurgical mechanisms for increasing strength lead to...
Article
Microstructural length-scale refinement is among the most efficient approaches to strengthen metallic materials. Conventional methods for refining microstructures generally involve grain size reduction via heavy cold working, compromising the material’s ductility. Here, a fundamentally new approach that allows load-driven formation and permanent re...
Article
While interstitial alloying has been utilized to improve mechanical properties of multi-component high entropy alloys (HEAs), its effectiveness depends on the interstitial content, microstructure and compositional homogeneity states. Here we present and discuss the influences of these factors on the mechanical behavior of interstitial equiatomic CoC...
Article
Full-text available
High-performance lightweight materials are urgently needed, given the pressing quest for weight reduction and the associated energy savings and emission reduction. Here, by incorporating the multi-principal element feature of compositionally complex alloys, we develop the concept of lightweight steels further and propose a new class of compositiona...
Article
Owing to the partial dislocation assisted twinning and/or displacive transformation upon stress loading, metastable high-entropy alloys (HEAs) and their interstitial variants have shown excellent strength-plasticity synergy. However, the fundamental mechanisms of the dislocation nucleation and the onset of plasticity in these emerging materials rem...
Article
The unavoidably formed rare-earth sesquioxide Sm2O3 microparticles in Sm2Co17-type magnets have been reported to deteriorate magnets’ magnetic properties but improve their mechanical and electrical performance. Here, we unveil the distribution, structure and elastic properties of Sm2O3 in a high-end Sm2Co17-type magnet. Results show that Sm2O3 micr...
Article
We design and investigate a ferritic multicomponent alloy with high electrical resistivity, low temperature coefficient of resistivity (TCR) in a wide-temperature range, high strength, and moderate deformability, aiming to overcome the bottlenecks limiting the development of cost-efficient high-quality resistors. The developed bulk alloy with nomin...
Article
Full-text available
Time-dependent plastic deformation, also known as creep, can occur in high-melting-point materials at room temperature when subjected to submicron plastic contact (e.g., components in micro-electronic mechanical systems) due to the extremely high stress conditions. Previous investigations of creep behavior at submicron scale mainly focus on uniform...
Article
Full-text available
Soft magnetic materials (SMMs) serve in electrical applications and sustainable energy supply, allowing magnetic flux variation in response to changes in applied magnetic field, at low energy loss 1. The electrification of transport, households and manufacturing leads to an increase in energy consumption due to hysteresis losses 2. Therefore, minim...
Article
Full-text available
CoCrNi multicomponent alloys with equiatomic and non-equiatomic concentrations are promising for achieving an excellent balance of strength and ductility. However, the correlations between elemental concentrations and deformation mechanisms of this alloy family need to be uncovered for further targeted alloy design. In this work, atomistic molecula...
Article
Hydrogen-assisted fatigue crack propagation behavior of a selective laser melted Inconel 718 alloy was investigated under in situ electrochemical hydrogen charging, and by multi-scale microstructural analysis. Results show that hydrogen significantly accelerates fatigue crack growth rate (FCGR), and such effect is intensified when decreasing load f...
Article
Tracer diffusion of the substitutional components in interstitial (CoCrFeNiMn)1-xCx high-entropy alloys with nominally x = 0.002, 0.005 and 0.008 (in at. fractions) is measured at elevated temperatures from 1173 to 1373 K. Two different characteristic effects of interstitial carbon addition on substitutional diffusion in these FCC alloys are distin...
Article
Full-text available
Deformation twinning is rarely found in bulk face-centered cubic (FCC) alloys with very high stacking fault energy (SFE) under standard loading conditions. Here, based on results from bulk quasi-static tensile experiments, we report deformation twinning in a micrometer grain-sized compositionally complex steel (CCS) with a very high SFE of~79 mJ/m...
Article
Full-text available
Deformation twinning is rarely found in bulk face-centered cubic (FCC) alloys with very high stacking fault energy (SFE) under standard loading conditions. Here, based on results from bulk quasi-static tensile experiments, we report deformation twinning in a micrometer grain-sized compositionally complex steel (CCS) with a very high SFE of ~79 mJ/m...
Preprint
Full-text available
Soft magnetic materials (SMMs) serve in electrical applications and sustainable energy supply, allowing magnetic flux variation in response to changes in applied magnetic field, at low energy loss1. The electrification of transport, households and manufacturing leads to an increase in energy consumption due to hysteresis losses2. Therefore, minimiz...
Article
Full-text available
We investigated the effects of interstitial N and C on the stacking fault energy (SFE) of an equiatomic CoCrNi medium entropy alloy. Results of computer modeling were compared to tensile deformation and electron microscopy data. Both N and C in solid solution increase the SFE of the face-centered cubic (FCC) alloy matrix at room temperature, with t...
Article
Full-text available
The chemical short-range order (CSRO) in a face-centered cubic equiatomic NiCoFeCrMn high-entropy alloy was revealed directly from advanced transmission electron microscopy in this work. Further, instead of controlling CSRO by conventional heat treatment, we show a new possibility of tailoring CSRO by radiation. The multiple types of atoms in such...
Article
Full-text available
There are several facets of aluminum when it comes to sustainability. While it helps to save fuel due to its low density, producing it from ores is very energy-intensive. Recycling it shifts the balance towards higher sustainability, because the energy needed to melt aluminum from scrap is only about 5% of that consumed in ore reduction. The amount...
Article
3D printing of high-strength alloys enables efficient manufacturing of complex metallic components. Yet, the as-built parts are often characterized by unsatisfied ductility due to micro-defects, requiring additional heat treatment to optimize the structure before in-site applications. The post heat-processing, however, often changes the shape of th...
Article
Full-text available
In this work, a design strategy based on a typical multi-principal element alloy (Fe50Mn30Co10Cr10, at. %) was proposed to tune the irradiation behavior by adding interstitial carbon atoms (Fe49.5Mn30Co10Cr10C0.5, at. %). Advanced scanning transmission electron microscopy was employed to study the evolution of dislocation loops and helium bubbles i...
Article
Full-text available
Previous tensile tests showed that the typical coarse-grained (CG) interstitial high entropy alloy (iHEA) with the nominal composition Fe49.5Mn30Co10Cr10C0.5 (at.%) has higher yield stress and better strain hardening at cryogenic conditions compared to that at room temperature. However, the yield stress of the fine-grained (FG) iHEA is little influ...
Article
Full-text available
Interstitials, e.g., C, N, and O, are attractive alloying elements as small atoms on interstitial sites create strong lattice distortions and hence substantially strengthen metals. However, brittle ceramics such as oxides and carbides usually form, instead of solid solutions, when the interstitial content exceeds a critical yet low value (e.g., 2 a...
Article
Full-text available
Crystalline metals and alloys are usually ductile owing to lattice dislocations and various slip systems, while bulk metallic glasses show ultra-high yield strength with very limited plasticity. Combining the crystalline and glassy phases in one alloy has recently been shown to be promising for achieving both ultrahigh strength and good deformabili...
Preprint
Full-text available
High-entropy alloys are solid solutions of multiple principal elements, capable of reaching composition and feature regimes inaccessible for dilute materials. Discovering those with valuable properties, however, relies on serendipity, as thermodynamic alloy design rules alone often fail in high-dimensional composition spaces. Here, we propose an ac...
Article
Polycrystalline metals with fine grains are highly possible to possess superplasticity via grain boundaries sliding (GBS). However, the mechanism of stabilizing the fine grains and releasing grain boundary strain incompatibilities to maintain GBS has puzzled the researchers for several decades. Here, a classic example is represented by the Au-Sn eu...
Article
The developments of multicomponent high-entropy alloys usually put emphasis upon the roles of multiple principal elements in optimizing the various properties. Instead of tuning the principal elements, here we propose to use multiple minor alloying elements to improve performance of HEAs. To this end, the microstructure and mechanical behavior of a...
Article
To develop novel Invar alloys in the practically infinite compositional space of multicomponent alloys, rapid alloy prototyping is used to investigate five multicomponent Invar alloys with 5 at.% addition of Al, Cr, Cu, Mn and Si to a super Invar alloy (Fe63Ni32Co5; at.%), respectively. All alloys show abnormally low thermal expansion coefficients...
Article
The hydrogen embrittlement behavior of C-doped and C-N co-doped non-equiatomic FeMnCoCr high-entropy alloys were investigated by slow strain rate tensile tests (1×10⁻⁵ s⁻¹) under in-situ electrochemical hydrogen charging. Multi-scale microstructural analysis suggests that appropriate phase stability and stacking fault energy adjusted by C-doping pr...
Preprint
Full-text available
Tracer diffusion of the substitutional components in (CoCrFeNiMn)$_{1-x}$C$_x$ high-entropy alloys with x = 0.002, 0.005 and 0.008 (in at. fractions) is measured at elevated temperatures from 1173 to 1373 K. Two different characteristic effects of interstitial carbon addition on substitutional diffusion in these FCC alloys are distinguished. At the...
Article
Full-text available
Over the past seventeen years, deformation behaviors of various types of high-entropy alloys (HEAs) have been investigated within a wide temperature range, from cryogenic to high temperatures, to demonstrate the excellent performance of HEAs under extreme conditions. It has been suggested that the dominated deformation mechanisms in HEAs would be v...
Preprint
Full-text available
Soft magnetic materials (SMMs) are indispensable components in electrified applications and sustainable energy supply, allowing permanent magnetic flux variations in response to high frequency changes of the applied magnetic field, at lowest possible energy loss1. The global trend towards electrification of transport, households and manufacturing l...
Article
Refractory high entropy alloys (RHEAs) are increasingly attractive for potential high temperature applications. To further optimize the mechanical properties, here we introduce intermetallic silicides into a RHEA (TaMo0.5NbZrTi1.5Al0.1) via Si alloying. Interdendritic eutectics composed of body-center cubic (bcc) matrix and hexagonal silicides are...
Article
Full-text available
The design of high performance structural materials is always pursuing combinations of excellent yet often mutually exclusive properties such as mechanical strength, ductility and thermal stability. Although crystal-glass composite alloys provide better ductility compared to fully amorphous alloys, their thermal stability is poor, due to heterogene...
Article
The design of high performance structural materials is always pursuing combinations of excellent yet often mutually exclusive properties such as mechanical strength, ductility and thermal stability. Although crystal-glass composite alloys provide better ductility compared to fully amorphous alloys, their thermal stability is poor, due to heterogene...
Article
Rapid solidification techniques such as electron beam additive manufacturing are considered as promising pathways for manufacturing Nb-Si based alloys for ultra-high-temperature applications. Here we investigate the microstructure diversity of a series of Nb-Si-Ti alloys via electron beam surface melting (EBSM) to reveal their rapid solidification...
Article
A bulk fine-grained W35Ta35Mo10Nb10V10 (at%) high-density high-entropy alloy (HEA) was successfully fabricated by mechanical alloying (MA) and spark plasma sintering (SPS) with varying parameters. Microstructure evolution and mechanical behavior of the HEA samples in various processing conditions were investigated. The alloying effect in the mixed...
Article
Full-text available
Wear-related energy and material loss cost over 2500 Billion Euro per year. Traditional wisdom suggests that high-strength materials reveal low wear rates, yet, their plastic deformation mechanisms also influence their wear performance. High strength and homogeneous deformation behavior, which allow accommodating plastic strain without cracking or...
Article
Full-text available
The lack of strength and damage tolerance can limit the applications of conventional soft magnetic materials (SMMs), particularly in mechanically loaded functional devices. Therefore, strengthening and toughening of SMMs is critically important. However, conventional strengthening concepts usually significantly deteriorate soft magnetic properties,...
Article
We demonstrate that modifying the cellular structures by well-controlled annealing can effectively improve the hydrogen embrittlement (HE) resistance of selective laser melting (SLM) processed alloys. Investigations on both as-SLM processed and annealed prototype CoCrFeMnNi high-entropy alloy samples suggest that annealing preserved the cellular st...
Article
The recently developed dual-phase (DP) non-equiatomic Fe50Mn30Co10Cr10 (at.%) high-entropy alloy (HEA) showed much higher strength and ductility compared to the single-phase equiatomic Fe20Mn20Ni20Co20Cr20 (at.%) HEA at room temperature. Herein we probe the cryogenic mechanical properties of the non-equiatomic DP-HEA with different grain sizes and...
Article
Full-text available
The variations in the pop-in behavior of an equiatomic CoCrFeMnNi high-entropy alloy under different hydrogen charging/discharging conditions were characterized via in-situ electrochemical nanoindentation. Results show that hydrogen accumulatively reduces both pop-in load and width, among which the reduction of pop-in width is more noticeable than...
Article
Full-text available
We present evidence of homogenization of atomic diffusion properties caused by C and N interstitials in an equiatomic single-phase high entropy alloy (FeMnNiCoCr). This phenomenon is manifested by an unexpected interstitial-induced reduction and narrowing of the directly experimentally determined migration barrier distribution of mono-vacancy defec...
Article
The mechanical behavior and corrosion resistance of a newly developed non-equiatomic Fe40Ni20Co20Cr20 (at.%) high-entropy alloy (HEA) were investigated. Excellent strength-ductility synergy with fracture elongation of more than 70% was found to be mediated by dislocation activities and nano-twinning. The alloy shows significantly improved corrosion...
Article
The micro-cracking behaviors of two high-entropy alloys (HEAs) of the FeMnCoCrNi family prepared by selective laser melting were systematically studied. Residual stresses were also analyzed by X-ray diffraction technique. Results show that the equiatomic FeMnCoCrNi HEAs with a relatively stable single-phase face-centered cubic (FCC) structure suffe...
Article
By considering the valence-electron concentration of 3d transition-metal alloys and compounds, we develop 3d high-entropy alloy Mn12.1Fe34.2Co33.5Ni12.3Cu7.9 with 8.7 electrons per atom, which is identical to that of Fe65Ni35 Invar. We carry out x-ray diffraction, scanning electron microscopy, magnetization, thermal expansion, and elastic modulus m...
Preprint
Full-text available
High-entropy alloys (HEAs) composed of multiple principal elements have been shown to offer improved radiation resistance over their elemental or dilute-solution counterparts. Using NiCoFeCrMn HEA as a model, here we introduce carbon and nitrogen interstitial alloying elements to impart chemical heterogeneities in the form of the local chemical ord...
Article
Full-text available
Since its first emergence in 2004, the high-entropy alloy (HEA) concept has aimed at stabilizing single-or dual-phase multi-element solid solutions through high mixing entropy. Here, this strategy is changed and renders such massive solid solutions metastable, to trigger spinodal decomposition for improving the alloys' magnetic properties. The moti...
Article
We report the chemical segregation and the phase decomposition as well as the microstructural response upon plastic deformation in a TaMo0.5ZrTi1.5Al0.1Si0.2 (at.%) refractory high entropy alloy (RHEA) by combining the thermodynamic calculation and the multiple experimental characterization techniques down to near-atomic scales. The alloy's composi...
Article
The corrosion resistance of the equiatomic CoCrNi medium-entropy alloy (MEA) and its 0.5 atomic % nitrogen alloyed variant in 0.1 M H2SO4 solution was investigated and compared with that of the 316L stainless steel as a reference material. All of the investigated materials showed single-phase face centered cubic (FCC) microstructures, and nitrogen...
Article
Twinning induced plasticity (TWIP) and phase transformation induced plasticity (TRIP) are two effective mechanisms for achieving good combination of strength and ductility in metallic materials, such as steels and high entropy alloys (HEAs). A further enhancement of the strength-ductility combination can be achieved by grain refinement owing to the...
Article
The metastability of a typical non-equiatomic FeMnCoCr high-entropy alloy (HEA) system was demonstrated to be dormant upon co-doping with C and N interstitials, i.e., displacive γ-ε phase transformation disappears during tensile deformation. Interestingly, we found in the present study that the displacive phase transformation prevails again in the...
Article
Full-text available
Discoveries of new multi-principal element alloys (MPEAs) with outstanding performance have been challenging due to the large complexity of the compositional space. Many existing highly alloyed steels already incorporate MPEA concepts and detailed research is readily available, which can be utilized for a more efficient design approach. Inspired by...
Article
To understand the relations among phase stability, microstructure and deformation behavior of a non-equiatomic quinary Fe 40 Mn 10 Co 20 Cr 20 Ni 10 (at.%) high-entropy alloy (HEA) with both transformation-and twinning-induced plasticity (TRIP & TWIP) effects, we systematically investigated the microstructural changes under different processing con...
Chapter
The design of iron-rich high-entropy alloys is discussed. Both substitutional and interstitial alloying elements are considered. The study of iron-rich high-entropy alloys by computational simulations based on alloy theory such as thermodynamic modeling and density functional based studies of alloy energetics and alloy excitations as well as the wi...
Article
Light-weight aluminum alloys are key structural materials widely used in transportation and constructions. Higher strength aluminum alloys are still urgently needed to further improve safety and energy efficiency. However, strength increase usually leads to higher difficulty of manufacturing and ductility loss of the final product. Also, most metal...