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Evolution of microstructures and mechanical properties with tempering temperature of a pearlitic quenched and tempered steel

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Journal of Iron and Steel Research International 2022年第9期29卷 1393-1403页

作者： De-zhen Yang Zhi-ping Xiong Chao Zhang Guan-zheng Feng Zhifang cheng xing-wang cheng School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Science and Technology on Materials under Shock and Impact Beijing 100081China

Instead of conventional quenching and tempering,fast austenitization from an initial microstructure of lamellar pearlite followed by quenching and tempering was carried out,leading to the formation of inhomogeneous *** comprised different morphologies of lath martensite and retained austenite(RA).The effect of tempering temperature on microstructure evolution and tensile properties was systematically *** increasing tempering temperature from 150 to 250℃,transition carbides gradually coarsened and their amount increased,the dislocation density in martensitic laths gradually decreased,and RA fraction decreased from 10.9%to 2.2%.The precipitation and dislocation strengthening can ensure a high strength,while RA can ensure a good ductility,leading to a simultaneous increase in the strength and ductility when decreasing tempering ***,the best combination of tensile properties(ultimate tensile strength of 2133±41 MPa and total elongation of 11.1%±1.3%)was achieved after tempering at 150℃.

关键词： Fast austenitization Pearlite Tempering Manganese Mechanical property

Microstructure and mechanical properties of a Cr-Ni-W-Mo steel processedthermo-mechanical controlled processing

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Journal of Iron and Steel Research International 2021年第6期28卷 713-721页

作者： Jia-xin Liang Ying-chun wang xing-wang cheng Zhuang Li Jin-ke Du Shu-kui Li School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Science and Technology on Materials Under Shock and Impact Beijing 100081China

Experiments were conducted to evaluate the microstructure and tensile properties of a medium carbon Cr-Ni-W-Mo steel processedthermo-mechanical controlled processing(TMCP)with cooling at different conditions in water,oil,air or lime followedlow *** to normal heat-treatment processing,TMCP with water-cooling after deformation enhances the yield strength and tensile strength of the steelabout 323 MPa and about 251 MPa,respectively,due to higher dislocation strengthening and grain boundary ***,it increases the elongation by ;about 1.76%attributed to the increase in volume percentage of the retained austenite and the refined laths of tempered *** the cooling rate after deformation during TMCP leads to a decrease in the *** results the coupling effectsthe reduction in dislocation density and volume fraction of tempered martensite together with the coarseness in martensite ***,cooling rate decreasing has less influences on ductility becathe improved elongation the increase in the volume fractions of both retained austenite and lower bainite together with dislocation density decreasing is compensatedthe reduced elongation coarsened grains.

关键词： Thermo-mechanical controlled processing Ultra-high strength steel Microstructure Bainite Tensile property

Factors Affecting the Mechanical Properties of Ultra-high-strength Bainitic Steel Containing W and 0.33 mass% C

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Journal of Iron and Steel Research International 2016年第3期23卷 289-296页

作者： Shi-meng ZHOU xing-wang cheng You-jing ZHANG Meng wang Wen JIANG Hong-nian CAI School of Materials Science and Engineering Beijing Institute of Technology National Key Laboratory of Science and Technology on Materials under Shock and Impact Beijing Institute of Technology

A novel ultra-high-strength bainitic steel was *** analysis of its mechanical properties by quasistatic testing showed that upper bainitic steel exhibited an ultimate tensile strength of 2 260 MPa（engineering stress）and an ultimate compressive strength of more than 2 700MPa（true stress）.The ultra-high strength of upper bainitic steel was mainly attributed to untempered martensite and upper bainite with a feather-like ***,lower bainitic steel demonstrated an ultimate tensile strength of 1 922 MPa（engineering stress）and an ultimate compressive strength of 2 500MPa（true stress）.The ultra-high strength of lower bainitic steel was primarily due to untempered martensite and lower bainite with an acicular *** untempered martensite in the two kinds of bainitic steels was produced in different *** dynamic test results showed that the ultimate compressive strengths of the two bainitic steels were maintained at 1 600MPa（true stress）under high strain rates（1 100and2 200s-1）at 600℃,because of the added tungsten,confirming the satisfactory hot hardness property of the ***,lower bainitic steel showed better comprehensive mechanical properties than upper bainitic steel.

关键词： upper bainite lower bainite bainitic ferrite retained austenite untempered martensite mechanical property

Corrosion behaviour of NiCrFeAl-hBN seal coatings in oxidation environments at a high temperature

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Rare Metals 2021年第1期40卷 212-218页

作者： Su-Yuan Yang Dan Guo xing-wang cheng Jian-Ming Liu Yue-Guang Yu School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081.China National Key Laboratory of Science and Technol Beijing General Research

The purpose of this investigation was to evaluate the microstructure,high-temperature oxidation behaviour,and hardness of a seal coating under controlled exposures at 750℃with different exposure *** results reveal that the main phases in the coating are Ni,FeNi3,and hexagonal BN,withα-Al_(2)O_(3)peaks appearing after 2-h *** the exposure time increases,the diffraction peak intensity ofα-Al_(2)O_(3)begins to decrease and Cr_(2)O_(3)peaks appear after 200 *** 1000 h,Cr_(2)O_(3)becomes dominant with only small amounts ofα-Al_(2)O_(3)*** high-temperature oxidation process of the coating includes three stages:the fast stage,transition stage,and slow *** oxidation rate is constant in each stage,and in the fast stage and slow stages with values of7.9×10^(-4)and 8.37×10^(-5)mg^(2)·cm^(-4)·s^(-1),***,α-Al_(2)O_(3)forms near the pores in the coating,followed by the formation of Cr_(2)O_(3).As the exposure time increases,oxidation penetrates into the interior of the coating along phase boundaries to form island-shaped inner oxide layers with high concentrations of Cr,Ni,and ***,hardness increases with increasing oxide percentage.

关键词： NiCrFeAl-hBN Seal coating Oxidation Microstructure High temperature

Chemical patterning enhanced by increasing quenching temperature in a medium-Mn steel

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Journal of Iron and Steel Research International 2023年第10期30卷 1916-1920页

作者： Chao Zhang Zhi-ping Xiong De-zhen Yang Valeriy Dudko xing-wang cheng National Key Laboratory of Science and Technology on Materials under Shock and Impact Beijing Institute of TechnologyBeijing 100081China Tangshan Research Institute Beijing Institute of TechnologyTangshan 063000HebeiChina Belgorod State University Belgorod 308015Russia

Chemical heterogeneity in high-temperature austenite is an effective way to tune the austenite-to-martensite transformation during *** effect of quenching temperature on microstructure evolution is investigated when the high-temperature austenite is *** fast austenitization from partitioned pearlite consisting of Mn-enriched cementite and Mn-depleted ferrite in Fe-0.29C-3.76Mn-1.50Si(wt.%)steel,quenching to room temperature and quenching to 130℃ followed by 400℃ partitioning are both *** increasing quenching temperature from 25 to 130℃,the amount of heterogeneous microstructure(lamellar ghost pearlite)increases from 10.6%to 33.6% and the thickness of Mn-enriched retained austenite film is increased from 31.9±5.9 to 51.5±4.4 nm,indicating an enhancement of chemical *** is probably ascribed to the reduction in driving force for austenite-to-martensite transformation,which requires a lower Mn content for austenite retention.

关键词： Heterogeneous microstructure Phase transformation Retained austenite Quenching temperature Chemical patterning

Adiabatic shear banding of hot-rolling Ti–6Al–4V alloy subjected to dynamic shearing and uniaxial dynamic compression

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Rare Metals 2015年第9期34卷 632-637页

作者： Yu-Meng Luo Jin-Xu Liu xing-wang cheng Shu-Kui Li Fu-Chi wang Wen-Wen Guo China National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and Engineering Beijing Institute of Technology

Effect of stress state including dynamic shearing and uniaxial dynamic compression on adiabatic shear banding(ASBing) of hot-rolling Ti–6Al–4V(TC4) alloy was investigated. The absorbed energy of specimen before failure was calculated to evaluate the susceptibility to adiabatic shear band(ASB) of TC4 alloy *** show that the susceptibility to ASB of hot-rolling TC4 alloy exhibits obvious anisotropy under both dynamic shearing and uniaxial dynamic compression conditions, but the anisotropy of susceptibility to ASB under dynamic shearing condition exhibits an opposite tendency with that under uniaxial dynamic compression condition. Under the condition of uniaxial dynamic compression, material shows the highest susceptibility to ASB when loaded along transverse direction(TD) of the hot-rolling TC4, while the lowest susceptibility when loaded along rolling direction(RD). However, under the condition of dynamic shearing,the material behaves in the opposite way, demonstrating the lowest susceptibility when loaded along TD of the hotrolling TC4, while the highest susceptibility when loaded along RD.

关键词： Adiabatic shear banding Ti alloy Dynamic compressi

Preparation and properties of W–Cu–Zn alloy with low W–W contiguity

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Rare Metals 2016年第3期35卷 242-248页

作者： Ling-Ling Zheng Jin-Xu Liu Shu-Kui Li Shuang Liu Qing-He Zou xing-wang cheng School of Materials Science and Engineering Beijing Institute of Technology Mudanjiang North Alloy Tool Co. Ltd

The W–Cu–Zn alloy with a-brass matrix and low W–W contiguity was prepared by method of electroless copper plating combined with spark plasma sintering（SPS） *** effects of process and parameters on the microstructure and mechanical properties of the alloy were *** W–Cu–Zn alloy with a relative density of 96 % and a W–W contiguity of about 10 % was prepared by original fine tungsten particles combined with wet mixing method and SPS solid-state sintering method at 800℃ for 10 *** microstructure analysis shows that Cu–Zn matrix consists of nano-sized a-brass grains,and the main composition is Cu3Zn *** nano-sized Cu was coated on the surface of tungsten particles by electroless copper plating method,and the fairly low consolidation temperature and short solid-state sintering time result in the nano-sized matrix *** dynamic compressive strength of the W–Cu–Zn alloy achieves to1000 MPa,but the alloy shows poor ductility due to the formation of the hard and brittle Cu3Zn *** fine-grain strengthening and the solution strengthening of the Cu–Zn matrix phase are responsible for the high Vickers microhardness of about 300 MPa for W–Cu–Zn alloy.

关键词： W–Cu–Zn alloy Spark plasma sintering Microstructure Mechanical properties Microhardness

Penetration performance of W/Cu double-layer shaped charge liners

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Rare Metals 2016年第2期35卷 184-191页

作者： Wen-Jian Dong Jin-Xu Liu xing-wang cheng Shu-Kui Li Qing-He Zou Wen-Qi Guo School of Materials Science and Engineering Beijing Institute of Technology Mudanjiang North Alloy Tool Co. Ltd.

Two kinds of W/Cu double-layer shaped charge liner（SCL） were prepared by chemical vapor deposition（CVD） combined with electroforming technique： A SCL with W inner layer and Cu outer layer, B SCL with Cu inner layer and W outer layer. The penetration properties of A and B SCLs were researched. The results show that the two SCLs can form continuous jet and the tip velocities of A and B jets are 7.4 and 6.3 km s^（-1）, respectively. The kinetic energy density（5.3 9 1011 J m-3） of A jet tip increases by 194.4 %compared with that（1.8 9 1011 J m-3） of B jet tip. B jet,however, exhibits deeper penetration depth at the same experimental conditions. The chemical component and microstructure of the area nearby the ballistic perforation were researched. Component analysis shows that both the jets are formed only from inner layer metal. Microstructure analysis shows that martensite and intermetallic form around ballistic perforation penetrated by A SCL due to the intensive interaction between W jet and steel target. The two kinds of newly formed ultrahard phases also hinder the jet from penetrating target further. As a result of relatively alleviative interaction between Cu jet and target, only solid solution rather than ultrahard phases forms around ballistic perforation penetrated by B SCL.

关键词： Shaped charge liner Jet Penetration performance Chemical vapor deposition Electroforming technique

Data-driven mapping-relationship mining between hardness and mechanical properties of dual-phase titanium alloys via random forest and statistical analysis

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Rare Metals 2024年第2期43卷 829-841页

作者： Hai-Chao Gong Qun-Bo Fan Hong-Mei Zhang xing-wang cheng Wen-Qiang Xie Kai Chen Lin Yang Jun-Jie Zhang Bing-Qiang Wei Shun Xu School of Materials Science and Engineering Beijing Institute of TechnologyBeijing100081China National Key Laboratory of Science and Technology on Materials Under Shock and Impact Beijing100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing401135China Department of Mechanical and Materials Engineering University of Nebraska-LincolnLincolnNE68588USA

In order to accelerate the research on the property optimization of titanium alloy based on high-throughput methods,it is necessary to reveal the relationship between hardness and other mechanical properties which is still *** this work,taking Ti20C alloy as research object,almost all the microstructure of dual-phase titanium alloys were covered by traversing over 100 heat treatment ***,massive experiments including microstructure characterization and performance test were conducted,obtaining 51,590 pieces of microstructure data and 3591 pieces of mechanical property ***,based on large-scale data-driven technology,the quantitative mapping relationship between hardness and other mechanical properties was deeply *** results of random forest models showed that the correlation between hardness(H)and Charpy impact energy(A_(k))(or elongation,A)was hardly dependent on the microstructure types,while the relationship between H and tensile strength(R_(m))(or yield strength,R_(p0.2))was highly dependent on microstructure ***,combined with statistical analysis,it was found that the relationship between H and Ak(or A)were negatively ***,the relationship between H and strength was positively linear for equiaxed microstructure,and strength was linked to d^(−1/2)(d,equivalent circle diameter)ofα-grains in the form of classical Hall–Petch formula;but for other microstructures,the relationships were ***,the above rules were nearly the same in the rolling direction and transverse ***,a"four-quadrant partition map"between H and R_(p0.2)/R_(m) was established as a versatile material-screening tool,which can provide guidance for on-demand selection of titanium alloys.

关键词： Dual-phase titanium alloy Data-driven Hardness Mapping relationship