JournalTOCs

Acta Metallurgica Sinica (English Letters)
Journal Prestige (SJR): 0.576

Citation Impact (citeScore): 2
Number of Followers: 7

Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1006-7191 - ISSN (Online) 2194-1289
Published by Springer-Verlag

[2349 journals]

Modification of Corrosion Resistance of the Plain Carbon Steels by Pulsed
Electric Current
- Authors: Jun-Yang Gao; Xue-Bing Liu; Hai-Fei Zhou; Xin-Fang Zhang
  Pages: 1233 - 1239
  Abstract: The fracture of pipelines caused by corrosion cracks and the resulting oil and gas leakage can lead to great environmental pollution and economic losses. These negative effects are due to serious corrosion of the plain carbon steels used for armor of flexible pipe in oil and gas transmission medium. However, corrosion resistance of carbon steel armors has yet to be improved. In this study, the relationship between corrosion resistance and pearlite fraction in the plain carbon steels has been investigated through the application of pulsed electric current. Based on immersion test and electrochemical measurement, pulsed electric current increases the corrosion resistance of the plain carbon steels by reducing the fraction of pearlite phase. Pitting corrosion, which tends to initiate by galvanic corrosion of ferrite and cementite, is therefore inhibited due to the decrease in pearlite fraction (mixture of ferrite and cementite) under electropulsing.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0746-0
  Issue No: Vol. 31, No. 12 (2018)
Solidification of Immiscible Alloys Under the Effect of Electric and
Magnetic Fields
- Authors: Hong-Xiang Jiang; Jiu-Zhou Zhao
  Pages: 1240 - 1248
  Abstract: Immiscible alloys have aroused considerable interests in the last decades on account of their special physical and mechanical properties and potential applications. A considerable number of researches have been implemented to investigate the solidification behaviors of immiscible alloys in electric and magnetic fields. It has been indicated that the magnetic field and electric current can remarkably affect the solidification process and microstructures of immiscible alloys. The solidification techniques under the effects of electric and magnetic fields have great potentials for the fabrication of immiscible alloys. This paper reviews the research work in this field in recent years.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0731-7
  Issue No: Vol. 31, No. 12 (2018)
Experimental Investigation on Formability of AZ31B Magnesium Alloy
V-Bending Under Pulse Current
- Authors: Xing-Rong Chu; Lei Wang; Shu-Xia Lin; Zhen-Ming Yue; Jun Gao
  Pages: 1249 - 1257
  Abstract: In this work, the influence of pulse current parameters on springback and bending force of magnesium alloy during electropulse-assisted (EPA) V-bending was investigated. The experimental results showed that pulse current can effectively reduce the springback and the bending force compared to the experiments without current. The frequency has a more significant influence on bending force and springback than electric current density. Electroplastic (EP) effect begins to work when pulse current parameters reach a threshold value. To explore the mechanism of EPA V-bending, the microstructure evolution and fracture surface of the bending specimen were studied. It was found that pulse current can promote the occurrence of dynamic recrystallization (DRX) of magnesium alloy compared to traditional hot forming process. The fracture mode of AZ31B under EPA V-bending evolves from brittle fracture to ductile fracture with increasing pulse current parameters. Based on the discussion of athermal and thermal effects of EP effect, the mechanism of pulse current to promote DRX is studied and athermal effect is proved to exist.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0734-4
  Issue No: Vol. 31, No. 12 (2018)
Fabrication of a Gradient Nano-/Micro-structured Surface Layer on an
Al–Si Casting Alloy by Means of Ultrasonic–Electropulsing Coupling
Rolling Process
- Authors: Xiao-Pei Li; Song-Zhu Kure-Chu; Toru Ogasawara; Hitoshi Yashiro; Hai-Bo Wang; Zi-Zhen Xu; Xiao-Hui Li; Guo-Lin Song; Guo-Yi Tang
  Pages: 1258 - 1264
  Abstract: By using a novel surface modification technique named ultrasonic–electropulsing coupling rolling (UECR) process on an Al–Si casting alloy rod, the surface of material was smoothened significantly. Meanwhile, a strengthened layer with a gradient change in hardness was obtained in the outer surface, corresponding to a homogeneous gradient nano-/micro-structure. The thickness of nanometer-thick laminated structures was at least 40 μm, which was much thicker than conventional ultrasonic rolling process. During UECR, the formation of the well-defined nanocrystalline structure was attributed to the high strain rate and simultaneous annealing process realized by ultrasonic impact and electropulsing treatment.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0736-2
  Issue No: Vol. 31, No. 12 (2018)
A Three-Dimensional Multi-scale Plasticity Model for Metal-Intermetallic
Laminate Composites Containing Phases of the L1 2 Structure
- Authors: Yana D. Lipatnikova; Vladimir A. Starenchenko; Yuliya V. Solov’eva; Larisa A. Valuiskaya
  Pages: 1265 - 1271
  Abstract: A three-dimensional plasticity model was developed and applied to metal-intermetallic laminate composites containing phases of the L12 structure. A multi-scale approach that combined the methods of continuum mechanics and dislocation kinetics was used. This model takes account of the different mechanisms of self-locking superdislocations, the dislocations and the dislocation walls’ density storage for each type of layer at the micro-scale. At the meso-scale, the solutions to the dislocation kinetics equations, in the form of stress–strain curves, were used to create the properties of a three-dimensional representative element. The numerical simulation study of the macroscopic deformation was carried out with the finite element method using the dynamic model of continuum mechanics, which included the classical conservation laws, constitutive equations and the equation of state. It was shown that the simulation results generated using this model were in good agreement with the mechanical tests conducted on the single crystals of the L12 structure. The model provides an excellent description of the high-temperature plastic strain superlocalization effect of single crystal intermetallics of the L12 structure. This paper describes the numerical results of the study of the tension and compression tests of metal-intermetallic laminate composites containing phases of the L12 structure. The model allows the description of the distribution of the accumulated plastic strain inhomogeneities and is capable of predicting the strengthening properties and plastic behaviour of the metal-intermetallic laminate composites containing phases of the L12 structure.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0737-1
  Issue No: Vol. 31, No. 12 (2018)
Enhanced Surface Mechanical Properties and Microstructure Evolution of
Commercial Pure Titanium Under Electropulsing-Assisted Ultrasonic Surface
Rolling Process
- Authors: Yong-Da Ye; Xiao-Pei Li; Zhi-Yan Sun; Hai-Bo Wang; Guo-Yi Tang
  Pages: 1272 - 1280
  Abstract: The effects of electropulsing-assisted ultrasonic surface rolling process on surface mechanical properties and microstructure evolution of commercial pure titanium were investigated. It was found that the surface mechanical properties were significantly enhanced compared to traditional ultrasonic surface rolling process (USRP), leading to smaller surface roughness and smoother morphology with fewer cracks and defects. Moreover, surface strengthened layer was remarkably enhanced with deeper severe plastic deformation layer and higher surface hardness. Remarkable enhancements of surface mechanical properties may be related to the gradient refined microstructure, the enhanced severe plastic deformation layer and the accelerated formation of sub-boundaries and twins induced by coupling effects of USRP and electropulsing. The primary intrinsic reasons for these improvements may be attributed to the thermal and athermal effects caused by electropulsing treatment, which would accelerate dislocation mobility and atom diffusion.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0738-0
  Issue No: Vol. 31, No. 12 (2018)
Effect of Temperature on the Dynamic Recrystallization of AZ31 Alloy with
Pulse Current
- Authors: Shu-Xia Lin; Xing-Rong Chu; Zhen-Ming Yue; Jun Gao
  Pages: 1281 - 1286
  Abstract: The tensile tests of AZ31 magnesium alloy were carried out under room temperature, 100, 150 and 200 °C with and without pulse current. The effect of temperature on dynamic recrystallization (DRX) of AZ31 alloy was studied at different conditions. One-parameter approach was used to analyze the critical conditions of DRX, the critical stress was obtained under different temperatures, and the related results were validated by metallography observation. The results showed that DRX of AZ31 alloy occurred at 200 °C without pulse current. When pulse current with 150 Hz/50 V parameter was applied at room temperature, DRX occurred, while DRX was not completed until temperature over 150 °C. With the analysis result of critical conditions of DRX based on one-parameter approach, the relationship between critical stress and peak stress obtained in this present study is σc = (0.746–0.773)σp.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0739-z
  Issue No: Vol. 31, No. 12 (2018)
Hot Tensile Behaviors and Microstructure Evolution of Ti-6Al-4V Titanium
Alloy Under Electropulsing
- Authors: Dong-Wei Ao; Xing-Rong Chu; Shu-Xia Lin; Yang Yang; Jun Gao
  Pages: 1287 - 1296
  Abstract: The effect of electropulsing on the mechanical behaviors and microstructures of Ti-6Al-4V titanium alloy was investigated by an uniaxial tensile test. Compared to the value measured in cold tensile test, the alloy exhibits lower ultimate tensile strength when the tensile deformation is assisted by electropulsing. The tensile elongation is found to vary non-monotonically with increasing root mean square (RMS) current density. Though decreasing at first, the tensile elongation increases with current density once the value exceeds 8.1 A/mm2. Through applying current with RMS current density of 12.7 A/mm2, the tensile elongation at strain rate 0.001 s−1 can be improved by 94.1%. In addition, it is observed that more remarkable electroplastic effect is induced by the higher peak current density under similar thermal effect. Microstructure analysis reveals that the low plasticity at 8.1 A/mm2 is attributed to the micro-void easily formation near the tips of acicular β phases. The enhanced ductility at higher current densities, on the other hand, is attributed to the dynamic recrystallization.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0735-3
  Issue No: Vol. 31, No. 12 (2018)
Mathematical modeling of nanodispersed hardening of FCC materials
- Authors: Oleg Matvienko; Olga Daneyko; Tatyana Kovalevskaya
  Pages: 1297 - 1304
  Abstract: The plastic deformation of the pipe made of Cu-based alloy hardened by incoherent nanoparticles and subjected to the uniform internal pressure was investigated. The limits of elastic and plastic resistance are determined. The insignificant excess in the limit of the elastic resistance enables the plastic deformation in the most part of the pipe wall. The densities of shear-forming dislocations and prismatic dislocation loops are higher in alloys strengthened with coarse particles than in alloys strengthened with fine particles. At small distances between the strengthening particles, this effect is the most pronounced.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0754-0
  Issue No: Vol. 31, No. 12 (2018)
Features of Electroplastic Effect in Alloys with Martensite Transformation
- Authors: Vladimir Stolyarov
  Pages: 1305 - 1310
  Abstract: Influence of different electric current modes (pulse and direct) on occurrence of the electroplastic effect under uniaxial tension in the coarse-grained alloys with martensite transformations is investigated. The materials are shape memory Ti49.3Ni50.7 alloy and metastable austenite transformation-induced plasticity (TRIP) steel. The paper contains experimental results of current impact on the “stress–strain” curves of the material. It has been taken an experimental measurement of the sample temperature during the test. It is shown that the shape of a stress–strain curves and type of the serrate plastic flow, connected with the martensitic transformation and electroplastic effect, depend on the current modes. Impact of pulse current and direct current suppresses shape memory and TRIP effect.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0747-z
  Issue No: Vol. 31, No. 12 (2018)
Effect of Transverse Static Magnetic Field on Droplets Transient and
Inclusions Evolution During the Electroslag Remelting Process of GCr15
Ingots
- Authors: Qiang Li; Yun-Bo Zhong; Chu-Xiong Sun; Huai Wang; Tian-Xiang Zheng; Wei-Li Ren; Zhong-Ming Ren
  Pages: 1311 - 1316
  Abstract: The voltage was recorded to investigate the influence of the static magnetic field on droplet evolution during the magnetically controlled electroslag remelting (MC-ESR) process. MC-ESR experiments were carried out under different remelting current, and transverse static magnetic fields (TSMF) of 85 mT, 130 mT and 160 mT were superimposed. Statistical work was performed to obtain the quantitative data of the droplets. The ASPEX Explorer was utilized to investigate the inclusions evolution of GCr15 ingots. The number of the droplets was 31 in 20 s during the traditional ESR process and reached 50 and 51 under the MC-ESR process with the TSMF of 85 mT and 130 mT, respectively. When compared the traditional ESR process with the MC-ESR process, the inclusions amount reduced 67%.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0801-x
  Issue No: Vol. 31, No. 12 (2018)
Structural Optimization of Electromagnetic Swirling Flow in Nozzle of Slab
Continuous Casting
- Authors: Xiao-Wei Zhu; De-Wei Li; Chun-Lei Wu; Katsukiyo Marukawa; Qiang Wang
  Pages: 1317 - 1326
  Abstract: During the slab continuous casting process, the flow field of molten steel in the mold plays a decisive role in the quality of the slab. In this paper, electromagnetic swirling flow in nozzle technology is proposed to control the flow field in mold. This technology can drive molten steel to rotate inside the submerged entry nozzle by electromagnetic force, thereby controlling the flow field. This research shows that it can reduce the impact of molten steel on the bottom of nozzle and partly reduce the negative pressure at the upper part of nozzle outlet which is even eliminated by optimizing the structure and angle of nozzle. The area of heat flux of the mold wall becomes larger, and the crest value of heat flux gets lower than that without swirling in nozzle and any nozzle optimization. The meniscus fluctuates smoothly, and the flow velocity at the top surface is within a reasonable range. The temperature field distribution in the mold is uniform which was beneficial to the growth of equiaxed crystal and decreased element segregation.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0808-3
  Issue No: Vol. 31, No. 12 (2018)
Intermetallic Evolution of Al–Si-Coated Hot Stamping Steel During
Modified Electrically Assisted Rapid Heating
- Authors: Kieu-Anh Dinh; Sung-Tae Hong; Tien Viet Luu; Moon-Jo Kim; Heung Nam Han
  Pages: 1327 - 1333
  Abstract: Modified electrically assisted (EA) rapid heating of Al–Si-coated hot stamping steel is suggested, and the intermetallic evolution in the coating during heating is experimentally investigated. In the modified EA rapid heating, a continuous electric current for a suitable duration is applied to a specimen to heat it to a temperature slightly below the melting temperature of the coating. The temperature of the specimen is then kept constant for a specified dwell time. The result of the microstructural analysis shows that the modified EA rapid heating could effectively increase the thickness of the intermetallic layer between the coating and steel substrate much faster than conventional furnace heating and induction heating. The effectiveness of EA rapid heating may be due to the athermal effect of the electric current on the mobility of atoms, in addition to the well-known resistance heating effect. EA rapid heating also provides a technical advantage in that partial austenization can be easily achieved by properly placing the electrodes, as demonstrated in the present study.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0740-6
  Issue No: Vol. 31, No. 12 (2018)
Improving the Solidified Structure by Optimization of Coil Configuration
in Pulsed Magneto-Oscillation
- Authors: Jing Zhao; Ji-Hao Yu; Ke Han; Hong-Gang Zhong; Ren-Xing Li; Qi-Jie Zhai
  Pages: 1334 - 1344
  Abstract: Using both numerical and experimental methods, we studied the effect of coil configuration of pulsed magneto-oscillation (PMO) on distribution of electromagnetic field, flow field and solidification structure with the same pulse current parameters in Al ingots. We designed and constructed three types of coils: surface pulsed magneto-oscillation, hot-top pulsed magneto-oscillation (HPMO) and combined pulsed magneto-oscillation (CPMO). PMO treatment refined the solidification structure in all the ingots. The configuration of the PMO, however, introduced differences in magnetic field intensity, electromagnetic force, Joule heat, flow field, equiaxed grain zone, grain size and growth direction of columnar grains. The largest equiaxed grain zone was found in CPMO treated ingot, and the smallest grain size was found in both HPMO and CPMO treated ingots. Numerical simulation indicated that difference in electromagnetic field and flow field resulted in differences in solidification structure. HPMO is more advantageous over others for large ingot production.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0799-0
  Issue No: Vol. 31, No. 12 (2018)
Influence of Joint EMSFN and M-EMS on Fluid Flow in the Mold During
Continuous Casting
- Authors: Oleksandr Tretiak; Qiang Wang; De-Wei Li; Xiao-Wei Zhu; Chun-Lei Wu; Ming He
  Pages: 1345 - 1355
  Abstract: Homogenization of physical properties and the chemical composition through the control of liquid metal flow is essential during the continuous casting production of billets. This work was aimed at obtaining improved finished products via continuous casting that implements two magnetic fields. These fields were realized via two electromagnetic stirring processes implemented in a single process: one in the nozzle and one in the mold. The qualitative effects of applying double electromagnetic stirring (EMS) were verified through numerical simulation of 178 mm × 178 mm square billets exposed to double electromagnetic fields during the continuous casting process. The accuracy of the numerical calculations was verified via physical experiments. In addition, the final simulation results were compared with the intermediate results, to determine the true effects of different EMS on the metal flow in the mold. The results revealed that casting using EMS with different directions of magnetic field in the mold and the nozzle has the best effect on the distribution of the fluid flow and minimal influence on the stability of the meniscus and yields the minimum metal-jet penetration into the mold.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0800-y
  Issue No: Vol. 31, No. 12 (2018)
Stages and Fracture Mechanisms of Lamellar Pearlite of 100-m-Long
Differentially Hardened Rails Under Long-Term Operation Conditions
- Authors: A. A. Yuriev; V. E. Gromov; V. A. Grishunin; Yu. F. Ivanov; R. S. Qin; A. P. Semin
  Pages: 1356 - 1360
  Abstract: Using the methods of transmission electron microscopy, the carbide phase evolution in surface layers of the differentially quenched rails is studied after the passed tonnage of 691.8 million tons at the depth up to 10 mm along the central axis and fillet of rail head. The action of two mutual supplement mechanisms of steel carbide phase transformation in surface layers at rail operation is established: (1) cutting mechanism of cementite particles with the following departure in the volume of ferrite grains or plates (in pearlite structure); (2) cutting mechanism and following dissolution of cementite particles, transfer of carbon atoms on dislocations (in Cottrell atmospheres and dislocation cores), transfer of carbon atoms by moving dislocations into ferrite grains volume (or plates) with the following repeated formation of nanosized cementite particles. The first mechanism is accompanied by the change in linear sizes and morphology of carbide particles. Cementite element composition change is not essential. Carbide structure change can take place during the second mechanism.
  PubDate: 2018-12-01
  DOI: 10.1007/s40195-018-0810-9
  Issue No: Vol. 31, No. 12 (2018)
Microstructure and Mechanical Properties of AZ31 Mg Alloy Fabricated by
Pre-compression and Frustum Shearing Extrusion
- Authors: Kun Sheng; Li-Wei Lu; Yao Xiang; Min Ma; Zhong-Chang Wang
  Abstract: The AZ31 Mg alloys were processed by 6% pre-compression and frustum shearing extrusion at various temperatures, and the microstructure, texture and mechanical properties of the resulting alloys are systematically investigated. The results show that the grain size monotonically increases from 6.4 to 12.6 μm and the texture intensity increases from 6.7 to 9.6 with the increase in the extrusion temperature. The combining effect of the pre-twinning and the frustum shearing deformation is found to contribute to the development of the weak basal texture in Mg alloys. The Mg alloy sheet produced at the extrusion temperature of 563 K exhibits excellent mechanical properties. The yield strength, ultimate tensile strength and elongation for the extruded alloys are 189.6 MPa, 288.4 MPa and 24.9%, respectively. Such improved mechanical properties are comparable or even superior to those of the alloys subjected to other deformation techniques, rendering the pre-compression and frustum shearing extrusion a promising way for further tailoring properties of Mg alloys.
  PubDate: 2018-11-13
  DOI: 10.1007/s40195-018-0843-0
Enhanced Wear Resistance of Ni/h-BN Composites with Graphene Addition
Produced by Spark Plasma Sintering
- Authors: Jiao Xu; Dan-Qing Yi; Qiang Cui; Bin Wang
  Abstract: Ni-based self-lubricating composites containing a fixed amount of hexagonal boron nitride (h-BN) (5 wt%) and different amounts of graphene (0–1.5 wt%) were prepared by ultrasonic dispersion, high-energy ball milling, and spark plasma sintering. The effects of the graphene content on the physical, mechanical, and wear properties of the Ni/h-BN composites were evaluated. These properties were first enhanced with increasing graphene content, reaching optimal behavior for a graphene content of 1 wt%, and then degraded with further graphene addition. Compared to the pure Ni/h-BN composite, the relative density, hardness, and bending strength of the composite with 1 wt% graphene increased by 2.7%, 7.4%, and 6.3%, respectively, while the friction coefficient decreased by 56% to 0.31, and a reduction in wear rate by a factor of 5–15 was observed. The mechanism for improving the wear properties of the composite with added graphene was due to the formation of a graphene lubricating film on the worn surface, which increased the load bearing capacity of the surface and enhanced lubrication during wear.
  PubDate: 2018-11-13
  DOI: 10.1007/s40195-018-0844-z
Effect of Electric Potentials on Microstructure, Corrosion and Wear
Characteristic of the Nitrided Layer Prepared on 2Cr13 Stainless Steel by
Plasma Nitriding
- Authors: Yang Li; Shang-Zhou Zhang; Jian-Xun Qiu; Yong-Yong He; Jun-Jie Xiu; Qian-Wen Ye; Zhong-Li Liu
  Abstract: Plasma nitriding is a widely used technology to enhance the surface performance and extend the service life of alloy parts. The current research mainly focuses on the influences of time, temperature, gas type and pressure parameters on nitriding behavior, while fewer studies have been conducted on the electric potential. This paper mainly reports the effect of the electric potential on nitriding behavior. Test conditions were set using cathodic, anodic and floating potentials in a plasma nitriding furnace. 2Cr13 stainless steel was nitrided at 450 °C for 5 h in an NH3 atmosphere. The experimental results show that the nitriding treatment can be well performed under the different electric potentials, but differences exist in microstructures, morphologies and performance results of the modified layers. The thickness and hardness values of the nitrided layer are ranked as follows: cathodic > anodic > floating potential. The anodic nitrided surface has an obvious particle deposition layer composed of nitrides and oxides. Electrochemical and tribological experiments show that the corrosion resistance and wear resistance were significantly improved after a nitriding treatment using the three electric potentials. Moreover, the floating nitriding treatment resulted in the best tribological performance and corrosion resistance.
  PubDate: 2018-11-09
  DOI: 10.1007/s40195-018-0836-z
Electropulsing-Induced Microstructural Changes and Their Effects on
Electrical Conductivity of Thin Films of an Al-doped ZnO
- Authors: Y. H. Zhu; C. M. Luk
  Abstract: Electropulsing-induced phase decompositions and microstructural changes in AZO-5 thin films were studied by X-ray diffraction, scanning electron microscopy, atomic force microscopy, Hall effect measurement and photoluminescence (PL) measurement techniques. It was found that the electropulsing induced phase decomposition started with spinodal decomposition, which was accompanied by discontinuous precipitation in the AZO-5 thin films. Both circular phase decompositions and the crystal orientation occurred. Inappropriate electropulsing might damage zones, which resulted in tremendous decrease in electrical conductivity. Circular changes in both the peak position and the width of the PL wavelength were observed in the EPT AZO-5 thin films. Formation of zones favored reducing the roughness of the thin film.
  PubDate: 2018-10-17
  DOI: 10.1007/s40195-018-0809-2