ISSN 0412-1961
CN 21-1139/TG
Started in 1956

About the Journal

  Current Issue
    , Volume 58 Issue 12 Previous Issue    Next Issue
    For Selected: View Abstracts Toggle Thumbnails
    Recent Advances in Open-Cell Porous Metal Materials for Electrocatalytic and Biomedical Applications
    XU Wence, CUI Zhenduo, ZHU Shengli
    Acta Metall Sin, 2022, 58 (12): 1527-1544.  DOI: 10.11900/0412.1961.2022.00369
    Abstract   HTML   PDF (1818KB) ( 216 )

    Open-cell porous metal materials are multifunctional lightweight materials that have attracted considerable attention in electrocatalysis and biomedicine owing to their large specific surface area, low bulk density, good specific strength, high conductivity, and high mass transfer. The morphology, porosity, composition, crystal structure, and other properties of open-cell porous metal materials can be controlled precisely by designing different metal systems and developing efficient preparation technologies. Therefore, the corresponding functional performance of open-cell porous metal materials, such as catalytic activity, selectivity, stability, and biocompatibility, can be improved further. This paper briefly describes the fabrication methods and principles of open-cell porous metal materials for electrocatalysis and biomedicine. In addition, the recent developments in open-cell porous metal materials for electrocatalysis and biomedicine are summarized. Finally, the future development directions of open-cell porous metal materials for electrocatalysis and biomedicine are proposed.

    Figures and Tables | References | Related Articles | Metrics
    Research paper
    Formation of Dynamic Recrystallization Zone and Characteristics of Shear Texture in Surface Layer of Hot-Rolled Silicon Steel
    JIANG Weining, WU Xiaolong, YANG Ping, GU Xinfu, XIE Qingge
    Acta Metall Sin, 2022, 58 (12): 1545-1556.  DOI: 10.11900/0412.1961.2021.00145
    Abstract   HTML   PDF (4545KB) ( 194 )

    The texture and microstructure varying between thicknesses of hot-rolled sheets can be inherited to the final recrystallized sheets in silicon steel and affect its magnetic properties. Deformed and dynamic recrystallized microstructures produced in the surface layers during hot rolling bring different shear textures. Based on the study of deformed shear textures in the surface layers of hot-rolled sheets, it is necessary to examine the shear textures in the dynamic recrystallization zone. The cast slabs of Fe-2.5Si-0.8Al silicon steels with columnar grains are hot rolled in multiple passes. This study investigates the formation of dynamic recrystallization zone and characteristics of shear texture using EBSD technique. Consequently, the distribution of different shear textures in the fine grain region is obtained. The results indicate that the dynamic recrystallization zone in the horizontal band appears in the subsurface layer; simultaneously, it is surrounded by deformed grains with different shear textures in hot-rolled sheets with 88% reduction. A Copper texture component easily appears in the sub-surface layer and becomes more than Goss and Brass texture components in dynamic recrystallization zone and the surrounding deformed matrix when subjected to heavy shearing. The Goss texture is weak in the dynamic recrystallization zone. This is because excessive shearing is harmful to the formation and retention of Goss texture. The proportion of Brass texture in the dynamic recrystallization zone is the same as that in the surrounding deformed matrix. Additionally, the shear textures of the laboratory hot-rolled sheets and the industrial hot-rolled sheets with 98.9% reduction are compared. In the industrial hot-rolled sheets, the Goss texture is most from the subsurface to the center layer (in the position between subsurface and center layers).

    Figures and Tables | References | Related Articles | Metrics
    Effects of Tempering Temperature on Microstructure and Low-Temperature Toughness of 1000 MPa Grade NiCrMoV Low Carbon Alloyed Steel
    ZHOU Cheng, ZHAO Tan, YE Qibin, TIAN Yong, WANG Zhaodong, GAO Xiuhua
    Acta Metall Sin, 2022, 58 (12): 1557-1569.  DOI: 10.11900/0412.1961.2021.00147
    Abstract   HTML   PDF (4430KB) ( 318 )

    The low carbon alloyed steel has been widely used in the shipbuilding and offshore structures owing to its high strength and toughness at low temperatures. To optimize the microstructure and mechanical properties of low carbon alloyed steel as well as investigate the relationship between them, this study focuses on the microstructure evolution and corresponding mechanical properties of a 1000 MPa grade NiCrMoV low carbon alloyed steel during tempering in the range of 450-650oC. Microstructures of lath martensite and autotempered martensite were obtained after hot rolling followed by direct water cooling to room temperature. The evolution of lath martensite and retained austenite on tempering was characterized using SEM and TEM. The distribution of the retained austenite was investigated using EBSD. The result shows that when the tempering temperature of the NiCrMoV low carbon alloyed steel is increased from 450oC to 550oC, the lath martensite recovers and the martensite-austenite component gradually decomposes. The retained austenite with 4.8% volume fraction was obtained after tempering at 600oC. The NiCrMoV low carbon alloyed steel obtained intercritical ferrite and fresh martensite when tempered at 650oC. The reverse transformation process of austenite was analyzed through a dilatometer curve. The partition behavior of alloying elements C, Ni, and Mn during intercritical tempering was analyzed kinetically through DICTRA simulation. An appropriate fraction of thermally stable retained austenite obtained at 600oC was attributed to the extent of partitioning of C, Ni, and Mn into the reversed austenite, which contributed to the best balance of strength-ductility-toughness properties. After direct quenching and tempering at 600oC, high yield strength of 1030 MPa with a high ductility of 18%, low yield to tensile ratio of 0.93, and excellent low-temperature toughness of 160 J at -80oC were obtained.

    Figures and Tables | References | Related Articles | Metrics
    Synergistic Effect of Magnetic Field and Grain Size on Martensite Nucleation and Variant Selection
    YUAN Jiahua, ZHANG Qiuhong, WANG Jinliang, WANG Lingyu, WANG Chenchong, XU Wei
    Acta Metall Sin, 2022, 58 (12): 1570-1580.  DOI: 10.11900/0412.1961.2021.00204
    Abstract   HTML   PDF (4565KB) ( 184 )

    Extrinsic (magnetic fields) and intrinsic (austenite grain sizes) factors can effectively control the martensitic transformation. Until now, research has mainly focused on the separate effects of magnetic fields and austenite grain sizes on the kinetics of the martensitic transformation. Systematic studies considering the coupling effects of magnetic fields and austenite grain sizes on the temperature at which martensite is formed (Ms), the final volume fraction of the transformed martensite, and the kinetics of the martensitic transformation during continuous cooling are still lacking. Furthermore, no study has yet been reported on the mechanism underlying how magnetic fields and austenite grain sizes affect the martensitic transformation. In this study, SUS321 stainless steel is used to investigate the effect of grain size on the kinetics and mechanisms of the martensitic transformation during continuous cooling from 300 K to 4 K under various magnetic fields by using the physical property measurement system (PPMS). The results show that at a constant grain size, the Ms temperature and the final amount of martensite increase as a function of the magnetic field magnitude. Under the same magnetic field, a critical austenite grain size exists, which obviously accelerates the martensitic transformation during cooling. Detailed microstructural characterizations also show that the external magnetic field effectively promotes the formation of ε nucleation sites, which consequently enhances the nucleation rate of α′-martensite and its transformation during further cooling. These findings provide mechanistic insights into the previously found phenomenological results. Additionally, in-depth crystallographic analyses also demonstrate that although the magnetic field promotes ε nucleation, the variant selection during the γε transformation is insensitive to the magnetic field magnitude, unlike the austenite grain size. Under the same magnetic field, the increase in the austenite grain size results in more ε variants during cooling. The collision of similar ε variants restricts the growth of martensite laths and retards the martensitic transformation in coarse-grained austenite. The variant selection of the final transformation εα′ is insensitive to the magnetic field magnitude and the austenite grain size.

    Figures and Tables | References | Related Articles | Metrics
    Effect of Welding Heat Input on Microstructure and Impact Toughness of the Simulated CGHAZ in Q500qE Steel
    ZHU Dongming, HE Jiangli, SHI Genhao, WANG Qingfeng
    Acta Metall Sin, 2022, 58 (12): 1581-1588.  DOI: 10.11900/0412.1961.2021.00175
    Abstract   HTML   PDF (3999KB) ( 159 )

    As China's economy enters a stage of high-quality development, it is important to study high-performance bridge steels with high strength, high toughness, high efficiency, and easy welding. Presently, coarse-grained heat-affected zones (CGHAZs) of high-performance bridge steels are prone to coarse-grain embrittlement, which reduces its impact toughness. To improve their low-temperature toughness, the relationship between their microstructure and impact toughness has been extensively researched and discussed. However, the control connection and internal mechanism between the bainite microstructure and impact toughness have not been clarified. In this study, the simulated samples of CGHAZs in Q500qE steel with varying heat inputs, from 15 to 30 kJ/cm, were reproduced in Gleeble 3500 thermal simulation-testing machine. The effect of different heat inputs on the microstructure, impact toughness of CGHAZs, and their inherent mechanism was discussed and analyzed in-depth using OM, SEM, and EBSD. The results indicate that the microstructure of each simulated sample of CGHAZs in Q500qE steel was composed of lath-like bainite (LB) and granular-like bainite (GB). The LB increased, the GB reduced, phase-transition temperature (Ar3) declined, and the bainitic packet/block substructure refined as the welding heat input decreased. In addition, with the decreased heat inputs, the Charpy impact energy (KV2) at -40oC of CGHAZs is enhanced because of the refined microstructure. The impact fracture of all samples showed cleavage fracture characteristics, and the cleavage face size of the simulated samples of CGHAZs decreased due to the reduced heat inputs. Compared with prior austenite grain boundary and bainite block, the bainite packet is the most effective microstructural unit for controlling the impact toughness of CGHAZs in Q500qE steel, and its boundary effectively facilitates the prevention of further propagation of a secondary crack.

    Figures and Tables | References | Related Articles | Metrics
    Austenite Grain Growth Behavior of Vanadium Microalloying Medium Manganese Martensitic Wear-Resistant Steel
    HAN Ruyang, YANG Gengwei, SUN Xinjun, ZHAO Gang, LIANG Xiaokai, ZHU Xiaoxiang
    Acta Metall Sin, 2022, 58 (12): 1589-1599.  DOI: 10.11900/0412.1961.2021.00560
    Abstract   HTML   PDF (5875KB) ( 250 )

    Medium manganese martensitic wear-resistant steel is a new type of wear-resistant steel with high hardenability and hardness; moreover, the controlling austenite grain size is of great significance for improving its comprehensive properties. In this study, the austenite growth behavior of vanadium microalloying medium manganese martensitic wear-resistant steel was systematically investigated using the Gleeble-3500 thermal simulation testing machine, OM, and HRTEM. The morphology, size, and particle size distribution of the second phase particles at different heating temperatures and holding times were analyzed. The influence of second phase particles on the growth behavior in austenite was also revealed. The results showed that the ultra-fine austenite grains with grain size of 3.98 μm were obtained when the sample was held at 820oC for 10 s. After holding for 3600 s, the average grain size of austenite only increased by 1.47 μm, and the austenite grains showed a strong ability to resist coarsening at 820oC. This could be attributed to the fine V(C, N) particles which could pin the austenite grain boundary and inhibit the growth of austenite grains. Furthermore, when reheating temperatures and holding times increase, the dissolution and coarsening of V(C, N) particles lead to the decrease of pining ability and then to the rapid growth of austenite. A new Sellars model with a time index was used to establish austenite growth model using a new method with a predetermined error function. The accuracy of the prediction for austenite grain sizes with new Sellars model was greatly improved compared with the traditional Beck model.

    Figures and Tables | References | Related Articles | Metrics
    Influence of Substrate Surface Structure on the Galvanizability of Fe-16Mn-0.7C-1.5Al TWIP Steel Sheet
    PENG Jun, JIN Xinyan, ZHONG Yong, WANG Li
    Acta Metall Sin, 2022, 58 (12): 1600-1610.  DOI: 10.11900/0412.1961.2021.00106
    Abstract   HTML   PDF (3801KB) ( 93 )

    Twinning-induced plasticity (TWIP) steels with a high Mn content show an advanced combination of strength and formability among the commercially available advanced high-strength steels for automotive applications. However, applying zinc coatings on TWIP steels using the continuous hot-dip galvanizing process remains a great challenge owing to the selective oxidation of Mn that occurs during continuous annealing before hot dipping. In this study, a potential procedure for improving the galvanizability of TWIP steels is developed and its mechanism is discussed. Both as-received cold-rolled and pretreated 16%Mn-0.7%C-1.5%Al (mass fraction) TWIP steel sheets were galvanized using the hot-dip process in a laboratory, and the influence of the substrate surface structure on the galvanizability of the TWIP steel sheets was studied. The wettability of molten zinc on the TWIP steel sheets was examined, and the coating adhesion was tested by bending at 180°. The elemental depth profiles of both the annealed and galvanized panels were analyzed via glow discharge optical emission spectroscopy, and the surface and cross-sectional morphologies were observed via SEM. Results indicated that a thin layer of fine ferrite grains produced using the pretreatment process could effectively improve the galvanizability of the TWIP steel. When the as-received cold-rolled TWIP steel was galvanized using the hot-dip process, the dominant external oxidation of Mn was observed on the steel surface before hot dipping, which prevented the formation of an Fe-Al inhibition layer and further resulted in poor galvanizability and deteriorated coating adhesion. When a thin layer of fine ferrite grains covered the TWIP steel surface, the galvanizability was considerably improved even though the ferrite layer thickness was less than 1 μm. The presence of surface ferrite grains almost completely suppressed the external oxidation of Mn during the annealing process, resulting in a clean surface similar to that of an interstitial-free or bake-hardened steel. Therefore, the wettability of molten zinc on the TWIP steel sheet improved considerably and a sufficient Fe-Al inhibition layer was formed. The formation of a thin layer of surface ferrite grains on the 16%Mn-0.7%C-1.5%Al TWIP steel facilitates a novel technique for addressing problems associated with galvanizability and coating adhesion.

    Figures and Tables | References | Related Articles | Metrics
    Corrosion Behaviors of Fe13Cr5Al4Mo Alloy in High-Temperature High-Pressure Water Environments
    LIN Xiaodong, MA Haibin, REN Qisen, SUN Rongrong, ZHANG Wenhuai, HU Lijuan, LIANG Xue, LI Yifeng, YAO Meiyi
    Acta Metall Sin, 2022, 58 (12): 1611-1622.  DOI: 10.11900/0412.1961.2021.00574
    Abstract   HTML   PDF (4211KB) ( 182 )

    FeCrAl alloys are promising candidate materials for accident-tolerant-fuel (ATF) claddings owing to their good high-temperature mechanical property, irradiation-swelling resistance, and high-temperature steam-oxidation performance. However, excellent corrosion resistance is also required in high-temperature high-pressure water environments when the alloys are used as ATF claddings. Therefore, in this work, the corrosion behavior of a Fe13Cr5Al4Mo alloy in 360oC, 18.6 MPa deionized water and 360oC, 18.6 MPa, 3.5 mg/L Li + 1000 mg/L B aqueous solution was studied. Results revealed that the weight gain and growth rate of the Fe13Cr5Al4Mo alloy were lower than that of the reference zirconium alloy, indicating a better corrosion property of the Fe13Cr5Al4Mo alloy. Moreover, an oxide film comprising Fe(Cr, Al)2O4 nanospinels formed on the Fe13Cr5Al4Mo alloy in both water environments, and Fe3O4 outer-oxide particles were observed in deionized water. The good corrosion performance of Fe13Cr5Al4Mo alloy was attributed to the compact spinel-oxide film, which could inhibit the diffusion of oxygen ions and metal cations. Adding Li + B into water changed the corrosion weight gain and oxide-film thickness of the Fe13Cr5Al4Mo alloy and impeded the formation of outer-oxide particles, which may be related to the high pH of alkaline Li + B aqueous solution and the interactions between Li+ and B3+.

    Figures and Tables | References | Related Articles | Metrics
    Corrosion Behavior of Q235 and Q450NQR1 Exposed to Marine Atmospheric Environment in Nansha, China for 34 Months
    LIU Yuwei, GU Tianzhen, WANG Zhenyao, WANG Chuan, CAO Gongwang
    Acta Metall Sin, 2022, 58 (12): 1623-1632.  DOI: 10.11900/0412.1961.2021.00576
    Abstract   HTML   PDF (2988KB) ( 206 )

    Many countries have begun to focus on the development and utilization of marine resources, involving ports, docks, oil production platforms, cross-sea bridges, large ships, and other marine engineering facilities, since beginning of the 21st century. Marine atmospheric corrosion issues encountered during construction put the safety of these marine engineering facilities in jeopardy. The Nansha Islands, which are located in the southernmost part of the South China Sea, are in a typical tropical marine atmosphere environment with no long-term corrosion data. The steel used in marine engineering is the premise of expanding marine space and exploiting marine resources, as well as the guarantee of enhancing marine national defense strength and safeguarding maritime rights and interests. Because of its poor corrosion resistance, the service life has certain limitations. As a result, studying the corrosion mechanism of carbon steel in this typical atmospheric environment after long-term exposure is crucial for engineers. The corrosion behavior of low carbon steel Q235 and weathering steel Q450NQR1 was investigated using the corrosion loss method, macroscopic morphology observation, SEM, XRD, and electrochemical and tensile tests after 34 months of exposure in the Nansha atmospheric environment. The results show that the corrosion dynamic of the two sheets of steel in the marine atmosphere of Nansha Islands can be divided into two stages. The corrosion rate of the second stage is smaller than that of the first stage. Weathering steel Q450NQR1 has demonstrated better corrosion resistance in a short exposure time. The rust layer on the skyward and field-ward sides of mild steel Q235 is thicker than that of weathering steel Q450NQR1 after 21 and 34 months of exposure, and there are more cracks in the rust layer, which could promote oxygen and chloridion diffusion to the substrate and speed up the corrosion process. The main components of corrosion products are γ-FeOOH, α-FeOOH, β-FeOOH, and Fe3O4, the relative contents of each product were different with the extension of exposure time. Furthermore, corrosion on the field-ward sides of the two steel sheets was worse than corrosion on the skyward sides. This is because the rust layer on the field-ward side was easily removed, resulting in a weakened resistance to corrosive medium. With the extension of exposure time, the thickness of the rust layer on the skyward side of carbon steel Q235 and weathering steel Q450NQR1 is increasing, and the tensile strength was gradually reduced. That is, Q235 and Q450NQR1 are more likely to fail owing to the thickening of the rust layer during use resulting in safety accidents.

    Figures and Tables | References | Related Articles | Metrics
    Constraint Related Fatigue Crack Initiation Life of GH4169 Superalloy
    GUO Haohan, YANG Jie, LIU Fang, LU Rongsheng
    Acta Metall Sin, 2022, 58 (12): 1633-1644.  DOI: 10.11900/0412.1961.2022.00099
    Abstract   HTML   PDF (3733KB) ( 190 )

    Nickel-based GH4169 superalloy is used as turbine disc material in aeroengines because of its good oxidation resistance, good formability, weldability, and high strength. However, turbine disc fatigue failure will inevitably occur in onerous service environments and after a long operation time. To ensure the safety and reliability of aeroengines, the fatigue damage behavior and fatigue life of GH4169 superalloy need to be studied. Constraint is an important factor affecting the fatigue fracture behavior of materials, because changing it will impact the fatigue behavior. To achieve a long service life and high reliability of aeroengines, fatigue and constraint effects must be researched. However, there are only limited studies on the effect of constraint on fatigue crack initiation time. In this study, a crystal plasticity constitutive model based on low cycle fatigue rate correlation was applied to the GH4169 superalloy. Two fatigue indicators, namely the cumulated energy dissipation and cumulated plastic slip, were introduced as fatigue crack initiation criteria to study the fatigue crack initiation time for different micro-notch depths and lengths. In addition, the relationship between constraint and fatigue crack initiation life was further investigated using the unified constraint parameter Ap. The results showed that both cumulated energy dissipation and cumulated plastic slip can accurately predict the fatigue crack initiation time. With the increase in micro-notch depth, the fatigue crack initiation time decreased, while it increased with the increase in micro-notch length. A linear relationship between the fatigue crack initiation time and Ap under different micro-notch depths and lengths was observed. Based on this relationship, the constraint related to the fatigue crack initiation time can be determined.

    Figures and Tables | References | Related Articles | Metrics
    Investigations on the Thermal Conductivity of Micro-Scale Cu-Sn Intermetallic Compounds Using Femtosecond Laser Time-Domain Thermoreflectance System
    ZHOU Lijun, WEI Song, GUO Jingdong, SUN Fangyuan, WANG Xinwei, TANG Dawei
    Acta Metall Sin, 2022, 58 (12): 1645-1654.  DOI: 10.11900/0412.1961.2021.00216
    Abstract   HTML   PDF (2437KB) ( 148 )

    An accurate temperature analysis of electronic packaging requires an understanding of the thermal-transport parameters of the material. However, studies on the thermal conductivity of intermetallic compounds (IMCs) in micro-interconnect solder joints are scarce, particularly common IMCs forming in Cu-Sn systems, which seriously affect the precise prediction of the temperature field and thermal stress for electronic packaging structures. This work proposes a novel method to quantitatively measure the thermophysical parameters of Cu-Sn IMCs based on the dual-wavelength femtosecond laser time-domain thermoreflectance (TDTR) system. Cu-Sn diffusion couple samples were prepared using a reflow and aging process. Two layers of Cu6Sn5 and Cu3Sn IMCs formed at the interface with micron thickness, and the (001) crystal plane of Cu6Sn5 was the preferred orientation. The sensitivity of the experimental parameters to the measurement parameters affects the fitting accuracy. Therefore, before testing, the effects of the aluminum transducer thickness and pump laser modulation frequency on the phase signal sensitivity in the thermal conductivity measurements of Cu6Sn5 and Cu3Sn were analyzed to help select the specific experimental parameters. After testing, the thermal conductivities of Cu6Sn5 and Cu3Sn were 47.4 and 87.6 W/(m·K), respectively, which are slightly higher than the previous results because of the microstructure discrepancy caused by different material preparation techniques. Finally, the influence of the pump laser diameter, aluminum transducer thickness, and material specific heat on the measurement error of thermal conductivity for Cu6Sn5 and Cu3Sn was examined. The test errors of the Cu6Sn5 and Cu3Sn thermal conductivity were -6.8%~4.6% and -7.1%~4.4%, respectively. Overall, the TDTR technology can evaluate the thermal-transport characteristics of micron-scale intermetallic compounds in electronic packaging and guide the thermal design and reliability evaluations of electronic components.

    Figures and Tables | References | Related Articles | Metrics