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Rare Metals 2022年第8期41卷 2864-2876页

作者： Chen-Liang Chu Wei-Ping Chen Jun-Chen Liu Qiang Chen Zhi-Qiang Fu Guangdong Key Laboratory for Advanced Metallic Materials Processing South China University of TechnologyGuangzhou510641China Southwest Technology and Engineering Research Institute Chongqing400039China

Cold rolling and post-deformation annealing(PDA)heat treatments were used to produce heterogeneous grain structures(HGS)in a single-phase face-centered cubic(fcc)Cr_(10)Co_(30)Fe_(30)Ni_(30)high-entropy alloy(HEA).The microstructural evolution and microstructure-property relationship of the HEA were systematically studied under different states.HGS could be achieved in PDA-treated samples at 875℃for 20 s and at 900℃for 20 s(PDA-900-20 s).PDA-900-20 s sample exhibits the most excellent combination of strength and ductility,showing a tensile yield strength of~590 MPa,an ultimate strength of~706 MPa and a total elongation of~23.9%.Additionally,compared with the homogenized counterpart exhibiting homogenous grains,PDA-900-20 s sample displays a notable increment of~413%in yield strength and simultaneously maintains a good ductility.The dominated strengthening mechanisms in PDA-900-20 s sample are grain-boundary strengthening and heterogeneous deformation-induced(HDI)strengthening,whereas the good ductility is mainly resulted from the HDI ductility.Accordingly,the present study provides an effective and simple pathway to overcome the strength-ductility tradeoff of typical fcc HEAs through heterogeneous microstructure.

关键词： High-entropy alloy Heterogeneous grain structures Hetero-deformation-induced hardening Mechanical properties Strengthening mechanism

A novel high-strength Al-La-Mg-Mn alloy for selective laser melting

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Journal of materials Science & Technology 2023年第6期137卷 205-214页

作者： Xinkui Zhang Liejun Li Zhi Wang Hanlin Peng Jixiang Gao Zhengwu Peng Guangdong Key Laboratory for Advanced Metallic Materials Processing South China University of TechnologyGuangzhou 510640China guangdong Provincial key laboratory of advanced Welding Technology China-Ukraine Belt and Road Joint Laboratory on Materials Joining and Advanced ManufacturingChina-Ukraine Institute of WeldingGuangdong Academy of SciencesGuangzhou 510650China guangdong Polytechnic Normal University Guangzhou 510635China

Developing high-strength Al-(La,Ce)alloys for additive manufacturing(AM)would entail considerable economic benefits.In this work,a novel near-eutectic Al-La alloy containing 5.50 wt.%Mg and 0.60 wt.%Mn was designed and fabricated via selective laser melting(SLM).Submicron Al_(11)La_(3)intermetallics with 3D continuous cellular-dendritic and granular morphologies were observed at the interior and boundary of the melt pool,respectively.Interestingly,these intermetallics are hierarchical and contained numerous Al_(6)Mn and Mg_(2)Si secondary nanoprecipitates.The as-fabricated alloy exhibited a tensile yield strength(YS)of 334 MPa and ultimate tensile strength(UTS)of 588 MPa at room temperature,which is the high-est UTS reported for Al-(La,Ce)alloys with an appreciable failure strain of∼6.4%.The 3D continuous cellular dendritic intermetallic and high Mg content afford significant strengthening and work harden-ing ability.In addition,the hierarchical feature of the intermetallics generated additional microcracks to coordinate the deformation.

关键词： Selective laser melting Al-La alloys 3D continuous structure Hierarchical precipitate High strength

Second phase refining induced optimization of Fe alloying in Zn:Significantly enhanced strengthening effect and corrosion uniformity

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International Journal of Minerals,Metallurgy and materials 2022年第4期29卷 796-806页

作者： Zhangzhi Shi Changheng Li Meng Li Xiangmin Li Luning Wang Beijing advanced Innovation Center for materials Genome Engineering Key Laboratory for Advanced Materials Processing of Ministry of EducationBeijing Laboratory of Metallic Materials and Processing for Modern TransportationSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China

Many non-toxic alloying elements,such as Fe,Ca,and Sr,have negligible solid solubilities in Zn matrix,leading to formation of coarse second phase particles.They exhibit low strengthening effects but highly detrimental to ductility.So refining second phase is a common pursuit for Zn alloys.The present paper takes Zn-0.3Fe alloy suffered from coarse FeZn_(13) second phase particles as a touchstone to testify microstructure refining effect through solidification with an accelerated speed and multi-pass rolling.FeZn_(13) particles are refined from 24 to 2μm,and Zn grains are refined to 5μm.As a result,the strengthening effect of Fe is enhanced significantly,with yield strength and the ultimate tensile strength of the alloy increased from 132 to 218 MPa and from 159 to 264 MPa,respectively.Furthermore,corrosion non-uniformity and penetration are much alleviated.These results show that microstructure refinement,especially on coarse intermetallic second phases,has a great potential to improve mechanical and degradation properties of biodegradable Zn alloys.

关键词： zinc alloys microstructure mechanical properties corrosion uniformity

Laser Powder Bed Fusion of Beta-Type Titanium Alloys for Biomedical Application:A Review

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 17-28页

作者： Xuan Luo Chao Yang Dongdong Li Lai-Chang Zhang State key laboratory of materials processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan430074China National Engineering Research Center of Near-Net-Shape Forming for metallic materials Guangdong Provincial Key Laboratory for Processing and Forming of Advanced Metallic MaterialsSouth China University of TechnologyGuangzhou510640China Centre for advanced materials and Manufacturing School of EngineeringEdith Cowan University270 Joondalup DriveJoondalupPerthWA6027Australia

Additive manufacturing ofβ-type titanium alloy is expected to replace Ti-6Al-4V alloy in the field of orthopedic implantation because of their low elastic modulus,excellent corrosion resistance,and biocompatibility.After briefly introducing the laser powder bed fusion(LPBF)process and physical phenomena,this paper reviews the recent progresses in LPBF-edβ-type Ti alloys.The strategies to strengthening and tougheningβ-type Ti alloys are critically reviewed.This is followed by the processing routes employed to achieve to low modulus for orthopedic applications,especially a new methodology for tailoring crystallographic orientation called multi-track coupled directional solidification.The effect of processing and compositions on performance metrics ofβ-type Ti alloys included corrosion behavior,and biocompatibility is reviewed.In the end,challenges in additive manufacturing ofβ-type Ti alloys in future are highlighted,with the aim to ensue clinical application of LPBF-edβ-type Ti alloys.

关键词： β-type Ti alloys Laser powder bed fusion Mechanical properties Elastic modulus Biocompatibility

Microstructure and Mechanical Behavior of FeNiCoCr and FeNiCoCrMn High-Entropy Alloys Fabricated by Powder Metallurgy

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Acta Metallurgica Sinica(English Letters) 2021年第4期34卷 445-454页

作者： Chenliang Chu Weiping Chen Zhen Chen Zhenfei Jiang Hao Wang Zhiqiang Fu Guangdong Key Laboratory for Advanced Metallic Materials Processing South China University of TechnologyGuangzhou 510640China Shantou Technician College Shantou 515041China

The present work reports a systematic investigation on phase evolution,microstructure and microstructure-property relationship of two typical face-centered cubic(FCC)structured high-entropy alloys(HEAs),FeNiCoCr and FeNiCoCrMn,prepared via mechanical alloying(MA)followed by spark plasma sintering(SPS).Following 50 h of MA,the two HEAs consisted of a mixture of FCC and body-centered cubic phases.Following SPS,the bulk FeNiCoCr alloy showed a primary FCC phase with a small amount of Cr_(23)C_(6) and Cr_(2)O_(3) contaminants,while the bulk FeNiCoCrMn alloy was composed of a primary FCC phase with some(Cr,Mn)23C6 and MnCr_(2)O_(4) contaminants.The average grain size of the primary FCC phase in the bulk FeNiCoCr alloy was~416 nm,while that of the primary FCC phase in the bulk FeNiCoCrMn alloy was~547 nm.The yield strength,compressive strength and strain-to-failure of the bulk FeNiCoCr alloy are 1525 MPa,1987 MPa and 24.4%,respectively,whereas those of the bulk FeNiCoCrMn alloy are 1329 MPa,1761 MPa and 21.9%,respectively.It suggests that the bulk FeNiCoCrMn exhibited lower strength and plasticity in comparison with the bulk FeNiCoCr alloy.Clearly,the smaller grain size of the primary FCC phase in the FeNiCoCr alloy is mainly responsible for the better mechanical performance.

关键词： High-entropy alloy Mechanical alloying Microstructure Strengthening Contaminants

Microstructural evolution and superelastic properties of ultrafine-graine d NiTi-base d shape memory alloy via sintering of amorphous ribbon precursor

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Journal of materials Science & Technology 2023年第7期138卷 80-92页

作者： W.S.Cai H.Z.Lu H.Z.Li Z.Liu H.B.Ke W.H.Wang C.Yang National Engineering Research Center of Near-net-shape Forming for metallic materials Guangdong Provincial Key Laboratory for Processing and Forming of Advanced Metallic MaterialsSouth China University of TechnologyGuangzhou 510640China Songshan Lake materials laboratory Dongguan 523808China Institute of Physics Chinese Academy of SciencesBeijing 100190China

NiTi-based shape memory alloys(SMAs)are considered as cutting-edge intelligent functional materials.However,it remains a great challenge to obtain ultrafine-grained(UFGed)bulk materials with mm-scale size as well as outstanding superelastic properties.Here,UFGed bulk Ti_(35)Zr_(15)Ni_(35)Cu_(15)NiTi-based SMA is successfully prepared via spark plasma sintering of amorphous ribbon precursor at different sintering temperatures,and microstructural evolution and superelastic properties are symmetrically investigated.It is found that its grain size ranges from UFG to micro-grain with increased sintering temperature regard-less of the predominant B2 matrix in all bulk samples.Interestingly,the orientation relationships between B2 matrix and nano-scale fcc(Ti,Zr)_(2)Ni precipitate evolve from coherent to incoherent.Consequently,the UFGed samples exhibit perfect superelasticity with the high recoverable strain of∼5.8%,the stable recov-ery rate above 99%,and the great critical stress inducing martensitic transformation higher than 1 GPa,far superior to the corresponding ones of suction-cast micro-grained TiZrNiCu SMAs.Fundamentally,the perfect superelasticity is attributed to the good resistance to dislocation slip or grain boundary slip by residual nano-scale amorphous phase or secondary phase of coherent and semi-coherent fcc(Ti,Zr)_(2)Ni precipitate.In addition,the gentle superelastic plateau is associated to the favorable transfer stress and the strong ability to accommodate dislocation movement,which is generated by the coherent interface between nano-scale fcc(Ti,Zr)_(2)Ni and UFGed B2 matrix.These results suggest that spark plasma sintering of amorphous alloy precursor is a feasible route to obtaining excellent superelasticity in NiTi-based SMAs.

关键词： Shape memory alloy Amorphous alloy Microstructure Superelasticity

An Al–Al interpenetrating-phase composite by 3D printing and hot extrusion

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International Journal of Minerals,Metallurgy and materials 2023年第4期30卷 678-688页

作者： Yulin Lin Di Wang Chao Yang Weiwen Zhang Zhi Wang School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510640China guangdong key laboratory for processing and Forming of advanced metallic materials South China University of TechnologyGuangzhou 510640China

We report a process route to fabricate an Al–Al interpenetrating-phase composite by combining the Al–Mg–Mn–Sc–Zr lattice structure and Al_(84)Ni_(7)Gd_(6)Co_(3)nanostructured structure. The lattice structure was produced by the selective laser melting and subsequently filled with the Al_(84)Ni_(7)Gd_(6)Co_(3)amorphous powder, and finally the mixture was used for hot extrusion to produce bulk samples. The results show that the composites achieve a high densification and good interface bonding due to the element diffusion and plastic deformation during hot extrusion.The bulk samples show a heterogeneous structure with a combination of honeycomb lattice structure with an average grain size of less than1 μm and nanostructured area with a high volume fraction of nanometric intermetallics and nanograin α-Al. The heterogeneous structure leads to a bimodal mechanical zone with hard area and soft area giving rise to high strength and acceptable plasticity, where the compressive yield strength and the compressive plasticity can reach ~745 MPa and ~30%, respectively. The high strength can be explained by the rule of mixture,the grain boundary strengthening, and the back stress, while the acceptable plasticity is mainly owing to the confinement effect of the nanostructured area retarding the brittle fracture behavior.

关键词： Al-based composites heterogeneous structure additive manufacturing mechanical properties

The precipitation behaviours and strengthening mechanism of a Cu-0.4 wt% Sc alloy

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Journal of materials Science & Technology 2022年第3期98卷 1-13页

作者： Zifan Hao Guoliang Xie Xinhua Liu Qing Tan Rui Wang State key laboratory for advanced Metals and materials University of Science and Technology BeijingBeijing100083China key laboratory for advanced materials processing of Ministry of Education Institute of Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing100083China Beijing laboratory of metallic materials and processing for Modern Transportation University of Science and Technology BeijingBeijing100083China

The precipitation behaviours during the aging process and the corresponding strengthening mechanism of a Cu-0.4 wt%Sc alloy were systematically investigated in this study.The phase transformation sequence of the precipitation in the aging process of the Cu-0.4 wt%Sc alloy was found to be:supersaturated solid solution→Sc-enriched atomic clusters→metastable phase→Cu4Sc phase.The tetragonal structured lamellar Cu4Sc precipitates,with a habit plane parallel to the{111}plane of the Cu matrix and orientation relationships of(022)_(α)//(211)_(Cu4Sc)and[011]_(α)//[113]_(Cu4Sc),are found homogeneously distributed in the matrix.A combined process of cryogenic rolling(CR)and aging was designed for optimization of the mechanical and electrical properties.Excellent integration of yield strength(696 MPa)and electrical conductivity(62.8%IACS)of this alloy was achieved by cryogenic rolling and subsequent aging process at 400℃for 4 h.The significant precipitation strengthening effect of this alloy is attributed to the Cu4Sc precipitates with an extremely small size of only 1.5–3 nm.The leading strengthening mechanism is considered as the superposition of both coherent strengthening and Orowan strengthening effects.

关键词： Cu-Sc alloy Precipitation Aging process Strengthening mechanism

Effect of compression direction on the dynamic recrystallization behavior of continuous columnar-grained CuNi10Fe1Mn alloy

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International Journal of Minerals,Metallurgy and materials 2015年第8期22卷 851-859页

作者： Yong-kang Liu Hai-you Huang Jian-xin Xie key laboratory for advanced materials processing of the Ministry of Education Institute of Advanced Materials and Technology University of Science and Technology Beijing Beijing laboratory of metallic materials and processing for Modern Transportation

The dynamic recrystallization（DRX） behavior of continuous columnar-grained（CCG） Cu Ni10Fe1 Mn alloy was investigated by hot compression along the solidification direction（SD） and perpendicular to the solidification direction（PD）. Specimens were compressed to a true strain of 0.8 at temperatures ranging from 25°C to 900°C and strain rates ranging from 0.01 to 10 s-1. The results indicate that DRX nucleation at grain boundaries（GBs） and DRX nucleation at slip bands（SBs） are the two main nucleation modes. For SD specimens, C-shaped bending and zig-zagging of the GBs occurred during hot compression, which made DRX nucleation at the GBs easier than that at the SBs. When ln Z ≤ 37.4（Z is the Zener–Hollomon parameter）, DRX can occur in SD specimens with a critical temperature for the DRX onset of;50°C and a thermal activated energy（Q） of 313.5 k J·mol-1. In contrast, in PD specimens, the GBs remained straight, and DRX nucleation occurred preferentially at the SBs. For PD specimens, the critical temperature is about 700°C, Q is 351.7 k J·mol-1, and the occurrence condition of DRX is ln Z ≤ 40.1. The zig-zagging of GB morphology can significantly reduce the nucleation energy at the GBs; as a result, DRX nucleation occurs more easily in SD specimens than in PD specimens.

关键词： copper–nickel alloys columnar grains compressive d

Discovery of aluminum alloys with ultra-strength and high-toughness via a property-oriented design strategy

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Journal of materials Science & Technology 2022年第3期98卷 33-43页

作者： Lei Jiang Changsheng Wang Huadong Fu Jie Shen Zhihao Zhang Jianxin Xie Beijing advanced Innovation Center for materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Beijing laboratory of metallic materials and processing for Modern Transportation Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China key laboratory for advanced materials processing(MOE) University of Science and Technology BeijingBeijing 100083China

Aluminum alloys with ultra-strength and high-toughness are fundamental structural materials applied in the aerospace industry.Due to the intrinsic restriction between strength and toughness,optimizing a desirable combination of these conflicting properties is always challenging in material development.In this study,171 sets of data were curated based on the characteristics of high-strength and high-toughness aluminum alloys in the literature.Then,a machine learning design system(MLDS)with a property-oriented design strategy was established to rapidly discover novel aluminum alloys with ductility and toughness indexes(with elongationδ=8%–10%and fracture toughness K_(IC)=33–35 MPa·m^(1/2))comparable to those of current state-of-the-art AA7136 aluminum alloys when the ultimate tensile strength(UTS)exceeded approximately 100 MPa,with values reaching 700–750 MPa.With the MLDS for experimental verification,three typical candidate alloys show satisfactory performance with UTS of 707–736 MPa,δof 7.8%–9.5%,and K_(IC)of 32.2–33.9 MPa·m^(1/2).The high contents of Mg and Zn alloying elements in the novel alloys form abundantη'phases,which produce a significant hardening effect,while the reasonable matching of Cr,Mn,Ti and Zr dispersoids refines the grain size.The decreased Cu content compared with that in the AA7136 alloy inhibits the formation of theσphase and S phase,so that the alloys show high toughness.

关键词： Aluminum alloy Machine learning Composition design Hardening mechanism Toughness