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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 182-187页

作者： ÇELİK Erçevik ATA ESENER Pınar ÖZTÜRK Esra AKSÖZ Sezen Nevşehir HacıBektaşVeli University Department of Physics50300NevşehirTurkey Erciyes University Graduate School of Natural and Applied Sciences38039KayseriTurkey Kocaeli University Department of Physics41380KocaeliTurkey

Ag-In intermetallic alloys were produced by using vacuum arc furnace. Differential Scanning Calorimetry(DSC) and Energy Dispersive X-Ray Spectrometry(EDX) were used to determine the thermal properties and chemical composition of the phases respectively. microhardness values of Ag-In intermetallics were calculated with Vickers hardness measurement method. According to the experimental results, Ag-34 wt%In intermetallic system generated the best results of energy saving and storage compared to other intermetallic systems. Also from the microhardness results, it was observed that intermetallic alloys were harder than pure silver and Ag-26 wt%In system had the highest microhardness value with 143.45 kg/mm^(2).

关键词： thermal properties microstructure characterization microhardness alloys material characterization

Effects of cooling rate on microstructure and microhardness of directionally solidified Galvalume alloy

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China Foundry 2024年第3期21卷 213-220页

作者： Ji-peng Li De-gao Qiao Jian Li Xiao-yang Luo Peng Peng Xian-tao Yan Xu-dong Zhang Gansu Jiu Steel Group Hongxing Iron and Steel Co. Ltd.Jiayuguan 735111GansuChina School of Materials and Energy Lanzhou UniversityLanzhou 730000China

The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is composed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich phase.In addition,the primary Al dendrites show significant refinement with an increase in the withdrawal speed.The relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 HV.This is a combined effect of grain refinement and second-phase strengthening.

关键词： Galvalume alloy directional solidification microstructure length scale microhardness

Multi-scale analyses of phase transformation mechanisms and hardness in linear friction welded Ti17(a+β)/Ti17(β)dissimilar titanium alloy joint

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Chinese Journal of Aeronautics 2024年第1期37卷 312-324页

作者： Zhenguo GUO Tiejun MA Xiawei YANG Ju LI Wenya LI Achilles VAIRIS State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Welding TechnologiesNorthwestern Polytechnical UniversityXi’an 710072China Aeronautical Key Laboratory for Welding and Joining Technologies AVIC Manufacturing Technology InstituteBeijing 100024China Mechanical Engineering Department University of West AtticaAthens 12241Greece

The Ti17(a+β)-Ti17(β)dual alloy-dual property blisk produced using Linear Friction Welding(LFW)is considered as high-performance component in advanced aeroengine.However,up to now,microstructure evolution and relationship between microstructure and micro mechanical properties of LFWed Ti17(a+β)/Ti17(β)dissimilar joint have not been thoroughly revealed.In this work,complex analyses of the phase transformation mechanisms of the joint are conducted,and phase transformations in individual zones are correlated to their microhardness and nanohardness.Results reveal that a dissolution occurs under high temperatures encountered during LFW,which reduces microhardness of the joint to that of Ti17(a+β)and Ti17(β).In ThermoMechanically Affected Zone of Ti17(a+β)(TMAZ-(a+β))side joint,a large number of nanocrystalline a phases form with different orientations.This microstructure strengthens significantly by fine grains which balances partial softening effect of a dissolution,and increases nanohardness of a phase and microhardness of TMAZ-(a+β).Superlattice metastableβphase precipitates from metastableβin Weld Zone(WZ)during quick cooling following welding,because of short-range diffusion migration of solute atoms,especiallyβstabilizing elements Mo and Cr.The precipitation of the superlattice metastableβphase results in precipitation strengthening,which in turn increases nanohardness of metastableβand microhardness in WZ.

关键词： Linear friction welding Ti17 titanium alloy Phase transformation microhardness Nanohardness

Microstructural characterization and mechanical properties of(TiC+TiB)/TA15 composites prepared by an in-situ synthesis method

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China Foundry 2024年第2期21卷 168-174页

作者： Zhi-yong Zhang Jiao-jiao Cheng Jia-qi Xie Shi-bing Liu Kun Shi Jun Zhao Shenyang Research Institute of Foundry Co. Ltd.CAMShenyang 110022China National Key Laboratory of Advanced Casting Technologies Shenyang 110022China

Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high modulus.In this study,the TA15-based composites reinforced with a volume fraction of 10% to 25%(TiB+TiC)were prepared using powder metallurgy and casting technique.Microstructural characterization and phase constitution were examined using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD).In addition,the microhardness,room temperature(RT)and high temperature(HT)tensile properties of the composites were evaluated.Results revealed that the reinforcements are distributed uniformly even in the composites with a high volume of TiB and TiC.However,as the volume fraction exceeds 15%,TiB and TiC particles become coarsening and exhibit rod-like and dendritic-like morphology.microhardness increases gradually from 321.2 HV for the base alloy to a maximum of 473.3 HV as the reinforcement increases to 25vol.%.Tensile test results indicate that a reinforcement volume fraction above 20% is beneficial for enhancing tensile strength and yield strength at high temperatures,but it has an adverse effect on room temperature elongation.Conversely,if the reinforcement volume fraction is below 20%,it can improve high-temperature elongation when the temperature exceeds 600℃.

关键词： titanium matrix composites microstucture microhardness tensile properties in-situ synthesis

Printability disparities in heterogeneous material combinations via laser directed energy deposition:a comparative study

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International Journal of Extreme Manufacturing 2024年第2期6卷 389-405页

作者： Jinsheng Ning Lida Zhu Shuhao Wang Zhichao Yang Peihua Xu Pengsheng Xue Hao Lu Miao Yu Yunhang Zhao Jiachen Li Susmita Bose Amit Bandyopadhyay School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819People’s Republic of China School of Machinery and Automation Wuhan University of Science and TechnologyWuhan 430081People’s Republic of China School of Mechanical Engineering Xi’an University of Science and TechnologyXi’an 710054People’s Republic of China Beijing Institute of Space Launch Technology Beijing 100076People’s Republic of China W.M.Keck Biomedical Materials Research Lab School of Mechanical and Materials EngineeringWashington State UniversityPullmanWA 99164United States of America

Additive manufacturing provides achievability for the fabrication of bimetallic and multi-material structures;however,the material compatibility and bondability directly affect the parts’formability and final quality.It is essential to understand the underlying printability of different material combinations based on an adapted process.Here,the printability disparities of two common and attractive material combinations(nickel-and iron-based alloys)are evaluated at the macro and micro levels via laser directed energy deposition(DED).The deposition processes were captured using in situ high-speed imaging,and the dissimilarities in melt pool features and track morphology were quantitatively investigated within specific process windows.Moreover,the microstructure diversity of the tracks and blocks processed with varied material pairs was comparatively elaborated and,complemented with the informative multi-physics modeling,the presented non-uniformity in mechanical properties(microhardness)among the heterogeneous material pairs was rationalized.The differences in melt flow induced by the unlike thermophysical properties of the material pairs and the resulting element intermixing and localized re-alloying during solidification dominate the presented dissimilarity in printability among the material combinations.This work provides an in-depth understanding of the phenomenological differences in the deposition of dissimilar materials and aims to guide more reliable DED forming of bimetallic parts.

关键词： directed energy deposition printability microstructure microhardness bimetallic parts

Parametric study of spark plasma sintering of Al_(20)Cr_(20)Fe_(25)Ni_(25)Mn_(10) high entropy alloy with improved microhardness and corrosion

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International Journal of Minerals,Metallurgy and Materials 2022年第1期29卷 119-127页

作者： Andries Mthisi Nicholus Malatji A.Patricia I.Popoola L.Rudolf Kanyane Department of Chemical Metallurgical and Materials EngineeringTshwane University of TechnologyP.M.B.X680PretoriaSouth Africa

Multicomponent Al_(20)Cr_(20)Fe_(25)Ni_(25)Mn_(10) alloys were synthesized using spark plasma sintering at different temperatures(800,900,and 1000℃)and holding times(4,8,and 12 min)to develop a high entropy alloy(HEA).The characteristics of spark plasma-synthesized(SPSed)alloys were experimentally explored through investigation of microstructures,microhardness,and corrosion using scanning electron microscopy coupled with energy dispersive spectroscopy(EDS),Vickers microhardness tester,and potentiodynamic polarization,respectively.Xray diffraction(XRD)characterization was employed to identify the phases formed on the developed alloys.The EDS results revealed that the alloys consisted of elements selected in this work irrespective of varying sintering parameters.The XRD,EDS,and scanning electron microscopy collectively provided evidence that the fabricated alloys were characterized by globular microstructures exhibiting face-centered cubic phase,which was formed on a basis of solid solution mechanism.This finding implies that the SPSed alloy showed the features of HEAs.The alloy produced at 1000℃ and holding time of 12 min portrayed an optimal microhardness of HV 447.97,but the value decreased to HV 329.47 after heat treatment.The same alloy showed an outstanding corrosion resistance performance.The increase in temperature resulted in an Al_(20)Cr_(20)Fe_(25)Ni_(25)Mn_(10) alloy with superior density,microhardness,and corrosion resistance over the other alloys developed at different parameters.

关键词： high entropy alloy spark plasma sintering microhardness corrosion

Microstructure and microhardness of aluminium alloy with underwater and in-air wire-feed laser deposition

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International Journal of Minerals,Metallurgy and Materials 2023年第4期30卷 670-677页

作者： Ning Guo Qi Cheng Yunlong Fu Yang Gao Hao Chen Shuai Zhang Xin Zhang Jinlong He State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China Shandong Provincial Key Laboratory of Special Welding Technology Harbin Institute of Technology at WeihaiWeihai 264209China Shandong Institute of Shipbuilding Technology Weihai 264209China School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China China Oil&Gas Pipeline Network Corporation Beijing 100101China

This study carried out the underwater and in-air wire-feed laser deposition of an aluminium alloy with a thin-walled tubular structure. For both the underwater and in-air deposition layers, both were well-formed and incomplete fusion, cracks, or other defects did not exist.Compared with the single-track deposition layer in air, the oxidation degree of the underwater single-track deposition layer was slightly higher.In both the underwater and in-air deposition layers, columnar dendrites nucleated close to the fusion line and grew along the direction of the maximum cooling rate in the fusion region(FR), while equiaxed grains formed in the deposited region(DR). As the environment changed from air to water, the width of DR and height of FR decreased, but the deposition angle and height of DR increased. The grain size and ratio of the high-angle boundaries also decreased due to the large cooling rate and low peak temperature in the water environment.Besides, the existence of a water environment benefitted the reduction of magnesium element burning loss in the DR. The microhardness values of the underwater deposition layer were much larger than those of the in-air layer, owing to the fine grains and high magnesium content.

关键词： wire-feed laser deposition microstructure magnesium element burn loss microhardness

Phase Selection and microhardness of Directionally Solidified AlCoCrFeNi_(2.1) Eutectic High-Entropy Alloy

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Acta Metallurgica Sinica(English Letters) 2022年第8期35卷 1281-1290页

作者： Peng Peng Shengyuan Li Weiqi Chen Yuanli Xu Xudong Zhang Zhikun Ma Jiatai Wang School of Materials Science and Energy Lanzhou UniversityLanzhou 730000China Gansu Institute of Metrology Lanzhou 730071China School of Physics and Electronic Information Engineering Qinghai Normal UniversityXining 810000China

In the present work,the solidification behaviors and microhardness of directionally solidified AlCoCrFeNi_(2.1) eutectic highentropy alloy(EHEA)obtained at different growth velocities are investigated.The microstructure of the as-cast AlCoCrFeNi_(2.1) EHEA is composed of bulky dendrites(NiAl phase)and lamellar eutectic structures,indicating that the actual composition of the alloy slightly deviates from the eutectic point.However,it is interesting to observe that the full lamellar structure of this alloy is obtained through directional solidification.In order to explain this phenomenon,the maximum interface temperature criterion and the interface response function(IRF)theory are applied to calculate the velocity range of the transition from the primary phase to the eutectic,which is 1.2–2×10^(4)μm/s.Furthermore,microhardness is one of the important parameters to measure the mechanical properties of materials.Therefore,the microhardness test is performed,and the test result indicates that the microhardness(HV)increased with increasing growth velocity(V)or decreased with increasing lamellar spacing(λ).The dependences ofλand HV on V are determined by using a linear regression analysis.The relationships between theλ,V and HV are given as:λ=11.62V^(-0.48),HV=305.5V 0.02 and HV=328.1λ^(0.04),respectively.The microhardness of the AlCoCrFeNi_(2.1) EHEA increases from 312.38 HV to 329.54 HV with the increase in growth velocity(5–200μm/s).Thus,directional solidification is an effective method to improve the mechanical properties of alloys.

关键词： Directional solidification Eutectic high-entropy alloy Phase selection Microstructure microhardness

Abrasion Resistance of Cement Paste with Granulated Blast Furnace Slag and Its Relations to microhardness and Microstructure

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Journal of Wuhan University of Technology(Materials Science) 2022年第3期37卷 410-415页

作者：陈晓润何真 CAI Xinhua ZHAO Rixu HU Lingling CHEN Hongren China West Construction Academy of Building Materials Chengdu 610015China China Construction Ready Mixed Concrete Co. Ltd.Wuhan 430205China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Shandong Chunhe New Material Research Institute Co. Ltd.Rizhao 276800China Hubei(Wuhan)Institute of Explosion Science and Blasting Technology Jianghan UniversityWuhan 430056China

The abrasion resistance of cement pastes with 30 wt%,40 wt%and 50 wt%granulated blast furnace slag(GBFS),and its relations to microhardness and microstructure like hydration products and pore structure were studied.Results indicated that GBFS decreased the abrasion resistance of paste,and among the pastes with GBFS,the paste with 40 wt%GBFS showed the highest abrasion resistance.The microhardness of GBFS was lower than that of the cement,and the microhardness of the hydration products in paste with GBFS was also lower than that of the hydration products in paste without GBFS,so that the abrasion resistance of paste decreased when GBFS was incorporated.The reason for the decrease of microhardness of pastes with GBFS was that the contents of Ca(OH)_(2)in pastes with GBFS was significantly lower than that in the paste without GBFS,while large amounts of calcium aluminate hydrates and hydrotalcite-like phases(HT)in pastes with GBFS were generated.Furthermore,among the pastes with GBFS,the paste with 40 wt%GBFS showed the lowest porosity which was the main reason for its highest abrasion resistance.

关键词： paste abrasion resistance granulated blast furnace slag microhardness microstructure

Friction welding influence on microstructure,microhardness and hardness behavior of CrNiMo steel(AISI 316)

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China Welding 2023年第3期32卷 21-27页

作者： Ammar Jabbar Hassan Billel Cheniti Brahim Belkessa Taoufik Boukharouba Djamel Miroud Nacer-Eddine Titouche Advanced Mechanics Laboratory(LMA) Houari Boumediene University of Sciences and TechnologyEl Alia 16111Bab EzzouarAlgiersAlgeria Research Center in Industrial Technologies Algiers 16014Algeria Science and Engineering Materials Laboratory(LSGM) Houari Boumediene University of Sciences and TechnologyEl Alia 16111Bab EzzouarAlgiersAlgeria Birine Nuclear Research Center Ain OusseraDjelfa 17200Algeria

For joining high Cr,Ni and Mo austenitic stainless steel(AISI 316)by direct drive friction welding(DDFW),with friction weld-ing conditions:rotation speed of 3000 r/min,friction time of 10 s,friction pressure of 130 MPa,forge time of 5 s and forge pressure of 260 MPa.The results of microstructure showed that the temperature at the interface reached 819℃while forge applied between 357-237℃,which subdivided welded joint into four distinct regions of highly plastically deformed zone(HPDZ),thermo-mechanically affected zone(TMAZ),heat affected zone(HAZ)and the base metal,with grain size about 10µm,100µm,90µm and 30µm respectively.These re-gions were created due to dynamic recrystallization(DRX)at the interface and thermo-mechanical deformation with heat diffusion in the neighboring regions.Whereas,high level of microhardness about 300 HV0.1 and hardness roughly 240 Hv10 at the interface due to HPDZ creation while low level of 240 HV0.1 for microhardness and moderately of 205 HV10 for hardness in neighboring regions.

关键词： friction welding austenitic stainless steel microstructure microhardness hardness