期刊文献+
共找到194篇文章
< 1 2 10 >
每页显示 20 50 100
Microstructure and Properties of AlCoCrFeNiTi High-Entropy Alloy Coatings Prepared by Laser Cladding 被引量:1
1
作者 Mengxian Li Zhiping Sun +1 位作者 Zhaomin Xu Zhiming Wang 《Journal of Harbin Institute of Technology(New Series)》 CAS 2024年第2期50-61,共12页
21-4N(5Cr21Mn9Ni4N)is extensively employed in the production of engine valves,operating under severe conditions.Apart from withstanding high-temperature gas corrosion,it must also endure the impact of cylinder explosi... 21-4N(5Cr21Mn9Ni4N)is extensively employed in the production of engine valves,operating under severe conditions.Apart from withstanding high-temperature gas corrosion,it must also endure the impact of cylinder explosion pressure.The predominant failure mode of 21-4N valves is abrasive wear.Surface coatings serve as an effective approach to prevent such failures.In this investigation,Laser cladding technology was utilized to fabricate AlCoCrFeNiTi high entropy alloy coatings onto the surfaces of 21-4N valves.According to the findings,the cladding zone has a normal dendritic microstructure,a good substrate-to-cladding layer interaction,and no obvious flaws.In terms of hardness,the cladding demonstrates an average hardness of 620 HV.The hardness has increased by 140%compared to the substrate.The average hardness of the cladding remains at approximately 520 HV even at elevated temperatures.Regarding frictional wear performance,between 400℃and 800℃,the cladding layer exhibits an average friction coefficient of 0.4,with the primary wear mechanisms being abrasive wear,adhesive wear,and a minor degree of plastic deformation. 展开更多
关键词 high entropy alloy laser cladding microstructure microstructure and properties
下载PDF
Effects of process parameters and annealing on microstructure and properties of CoCrFeMnNi high-entropy alloy coating prepared by plasma cladding 被引量:1
2
作者 Shi-yong Wei Chao-min Wang +4 位作者 Wen-yi Peng Ru-kai Luo Yun Chen Zhen-zhen Wan Yin Jin 《China Foundry》 SCIE EI CAS CSCD 2023年第6期491-502,共12页
Plasma cladding was used to prepare a CoCrFeMnNi high-entropy alloy(HEA)coating under different conditions.The process parameters were optimized using an orthogonal experiment design based on surface morphology qualit... Plasma cladding was used to prepare a CoCrFeMnNi high-entropy alloy(HEA)coating under different conditions.The process parameters were optimized using an orthogonal experiment design based on surface morphology quality characteristics,dilution rate,and hardness.The optimal process parameters were determined through range and variance analysis to be a cladding current of 70 A,a cladding speed of 7 cm·min^(-1),and a powder gas flow rate of 8 L·s^(-1).During the optimized experiments,both the cladded and annealed CoCrFeMnNi HEA coatings exhibit some pores,micro-voids,and a small amount of aggregation.However,the aggregation in the annealed coating is more dispersed than that in the cladded coating.The cladded CoCrFeMnNi HEA coating consists of simple FCC phases,while a new Cr-rich phase precipitates from the FCC matrix after annealing the coating at a temperature range of 550°C-950°C.After annealing at 850°C,the proportion of the FCC phase decreases compared to the cladded coating,and the number of large-angle grain boundaries is significantly reduced.However,the proportion of grains with sizes below 50μm increases from 61.7%to 74.3%.The micro-hardness and wear resistance of the cladded coating initially increases but then decreases with an increase in annealing temperature,indicating that appropriate annealing can significantly improve the mechanical properties of the CoCrFeMnNi HEA coatings by plasma cladding.The micro-hardness of the CoCrFeMnNi HEA coatings after annealing at 650°C increases to 274.82 HV_(0.2),while the friction coefficient decreases to below 0.595. 展开更多
关键词 plasma cladding CoCrFeMnNi HEA coating process optimization ANNEALING microstructure and mechanical property
下载PDF
Influences of oxide content and sintering temperature on microstructures and mechanical properties of intragranular-oxide strengthened iron alloys prepared by spark plasma sintering
3
作者 Deyin Zhang Xu Hao +4 位作者 Baorui Jia Haoyang Wu Lin Zhang Mingli Qin Xuanhui Qu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第9期1748-1755,共8页
How to increase strength without sacrificing ductility has been developed as a key goal in the manufacture of high-performance metals or alloys. Herein, the double-nanophase intragranular yttrium oxide dispersion stre... How to increase strength without sacrificing ductility has been developed as a key goal in the manufacture of high-performance metals or alloys. Herein, the double-nanophase intragranular yttrium oxide dispersion strengthened iron alloy with high strength and appreciable ductility was fabricated by solution combustion route and subsequent spark plasma sintering, and the influences of yttrium oxide content and sintering temperature on microstructures and mechanical properties were investigated. The results show at the same sintering temperature,with the increase of yttrium oxide content, the relative density of the sintered alloy decreases and the strength increases. For Fe–2wt%Y_(2)O_(3)alloy, as the sintering temperature increases gradually, the compressive strength decreases, while the strain-to-failure increases. The Fe–2wt%Y_(2)O_(3)alloy with 15.5 nm Y_(2)O_(3)particles uniformly distributed into the 147.5 nm iron grain interior sintered at 650℃ presents a high ultimate compressive strength of 1.86 GPa and large strain-to-failure of 29%. The grain boundary strengthening and intragranular second-phase particle dispersion strengthening are the main dominant mechanisms to enhance the mechanical properties of the alloy. 展开更多
关键词 oxide dispersion strengthening spark plasma sintering microstructure and properties strengthening mechanism
下载PDF
Microstructure characterization and mechanical properties of TC4-DT titanium alloy after thermomechanical treatment 被引量:12
4
作者 彭小娜 郭鸿镇 +2 位作者 石志峰 秦春 赵张龙 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第3期682-689,共8页
Influence of thermomechanical treatments (mill annealing, duplex annealing, solution treatment plus aging and triple annealing) on microstructures and mechanical properties of TC4-DT titanium alloy was investigated.... Influence of thermomechanical treatments (mill annealing, duplex annealing, solution treatment plus aging and triple annealing) on microstructures and mechanical properties of TC4-DT titanium alloy was investigated. Results showed that thermomechanical treatments had a significant influence on the microstructure parameters and higher annealing and aging temperature and lower cooling rate led to the decrease of the volume fraction of primaryαand the size of prior-βand the increase of the width of grain boundary αand secondary α. The highest strength was obtained by solution treatment and aging due to a large amount of transformedβand finer grain boundaryαand secondaryαat the expense of slight decrease of elongation and the ultimate strength, yield strength, elongation, reduction of area were 1100 MPa, 1030 MPa, 13%and 53%separately. A good combination of strength and ductility has been obtained by duplex annealing with the above values 940 MPa, 887.5 MPa, 15%and 51%respectively. Analysis between microstructure parameters and tensile properties showed that with the volume fraction of transformedβphase and the prior-βgrain size increasing, the ultimate strength, yield strength and reduction of area increased, but the elongation decreased. While the width of grain boundary α and secondary α showed a contrary effect on the tensile properties. Elimination of grain boundaryαas well as small prior-βgrain size can also improve ductility. 展开更多
关键词 TC4-DT titanium alloy thermomechanical treatment microstructures tensile properties
下载PDF
Effect of arc-ultrasound on microstructures and mechanical properties of plasma arc welded joints of SiC_p/Al MMCs 被引量:2
5
作者 雷玉成 王志伟 陈希章 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第2期272-277,共6页
The effect of arc-ultrasound on microstructures and mechanical properties of SiCp/6061A1 MMCs joints produced by arc-ultrasound plasma arc "in-situ" alloy-welding with different excitation frequencies was investigat... The effect of arc-ultrasound on microstructures and mechanical properties of SiCp/6061A1 MMCs joints produced by arc-ultrasound plasma arc "in-situ" alloy-welding with different excitation frequencies was investigated, in which argon-nitrogen mixture was used as plasma gas, Ti wire as filler and the arc-ultrasound was produced by modulating the plasma arc with high frequency. The results show that arc-ultrasound could refine the new reinforced composites such as TiC, TiN significantly, and improve their distribution greatly. And new phase A13Ti becomes finer and less. The test results of mechanical properties indicate that the maximum tensile strength of welded joints is gained when the excitation frequency is 50 kHz, and the maximum is 225 MPa, raising by about 7% comoared with conventional nlasma arc welding (PAW) (20q MPa). 展开更多
关键词 SiCp/A1 MMCs arc-ultrasound plasma arc welding microstructure and property
下载PDF
Characterization of Nano-Silica Local Metakaolin Based-Geopolymer: Microstructure and Mechanical Properties
6
作者 Zeineb Zidi Mounir Ltifi Idrees Zafar 《Open Journal of Civil Engineering》 2020年第2期143-161,共19页
The current study focused on the utilization of local clay for synthesis and characterization of meta-kaolin based geopolymers with and without nano-silica. The control geopolymers, for a compressive strength of 30 MP... The current study focused on the utilization of local clay for synthesis and characterization of meta-kaolin based geopolymers with and without nano-silica. The control geopolymers, for a compressive strength of 30 MPa, were optimized by using Liquid/Solid ratio of 0.55, NaOH concentration of 10 M and curing at 80<span style="white-space:nowrap;">°</span>C. The nano silica was added in an extended range of 1%, 2%, 3%, 5%, 7% and 10%. The synthesized nano-silica metakaolin based geopolymers w<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">as</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> investigated by using compressive strength, XRD, XRF, FTIR, SEM, MIP, TG, UV/VIS spectroscopy, in addition to density, water absorption and initial setting times. The results indicated an increase in the compressive strength value with the incorporation of nano-silica in geopolymer mixes until the optimum percentage of 5%, while the 10% addition of nano-silica decreased the compressive strength by 5% as compared to the control geopolymer. The increase in the compressive strength was accredited to the increase in the content of N-A-S-H gel and the amorphous structure as shown by XRD and FTIR analysis. In addition, the optical transmittance analysis, MIP and SEM scans along with the results of density and water absorption have clearly shown the densification of the matrix formed for the optimal percentage of nano-silica. However, the initial setting time was found to reduce substantially with increase of nano-silica content. Moreover, the TG results have shown the 5% nano-added geopolymers to have greater thermal stability as compared to reference geopolymer</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">. Finally, the adopted methodology in this research has shown that 5% nano-silica, is the optimal result for the synthesis and the production of local meta kaolin based geopolymer, with regard to the improvement of physical properties, micro structure and compressive strength.</span></span></span> 展开更多
关键词 GEOPOLYMER NANO-SIO2 Local-Metakaolin Mechanical properties microstructure properties
下载PDF
Mechanism of Effects of Rare Earths on Microstructure and Properties at Elevated Temperatures of AZ91 Magnesium Alloy 被引量:19
7
作者 张国英 张辉 +1 位作者 高明 魏丹 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第3期348-351,共4页
By using real-space recursion method,the energetics of the undoped and Al and/or RE atoms doped 7(1450)〈0001〉 symmetric tilt grain boundaries(GBs)in AZ91 alloys were investigated.Similar calculations were perfor... By using real-space recursion method,the energetics of the undoped and Al and/or RE atoms doped 7(1450)〈0001〉 symmetric tilt grain boundaries(GBs)in AZ91 alloys were investigated.Similar calculations were performed on undoped and doped bulk α Mg for comparison.The results showed that Al atoms segregated at GBs in AZ91 alloys.When RE atoms were added,they also segregated at GBs,and their segregation is stronger than Al atoms'.Therefore,RE atoms retard the segregation of Al atoms.Calculations of interaction energy indicated that Al atoms repelled each other,and could form ordered phase with host Mg atoms.On the contrary to the case of Al,RE atoms attracted each other,they could not form ordered phase with Mg,but could form clusters.Between RE and Al,there existed attractive interaction,and this attractive interaction was the origin of Al11RE3 precipitation.Precipitation of Al11RE3 particles with high melting point and high thermal stability along GB improves high temperature properties of AZ91 alloys. 展开更多
关键词 electronic structure ALLOYING grain boundary aggregation microstructure and properties of magnesium alloy rare earths
下载PDF
Effects of calcium addition on as-cast microstructure and mechanical properties of Mg-5Zn-5Sn alloy 被引量:9
8
作者 杨明波 程亮 潘复生 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第5期769-775,共7页
The effects of Ca addition on the as-cast microstructure and mechanical properties of the Mg-5Zn-5Sn (mass fraction,%) alloy were investigated.The results indicate that an addition of 0.5%-1.5% (mass fraction) Ca to t... The effects of Ca addition on the as-cast microstructure and mechanical properties of the Mg-5Zn-5Sn (mass fraction,%) alloy were investigated.The results indicate that an addition of 0.5%-1.5% (mass fraction) Ca to the Mg-5Zn-5Sn alloy not only refines the as-cast microstructure of the alloy but also causes the formation of the primary and/or eutectic CaMgSn phases with high thermal stability;an increase in Ca amount from 0.5% to 1.5% (mass fraction) increases the amount and size of the CaMgSn phase.In addition,Ca addition to the Mg-5Zn-5Sn alloy improves not only the tensile properties at room temperature and 150 ℃ but also the creep properties.Among the Ca-containing Mg-5Zn-5Sn alloys,the one added 0.5% (mass fraction) Ca obtains the optimum ultimate tensile strength and elongation at room temperature and 150 ℃,however,the alloy added 1.5% (mass fraction) Ca exhibits the optimum yield strength and creep properties. 展开更多
关键词 magnesium alloy Mg-5Zn-5Sn alloy microstructure and properties Ca addition
下载PDF
Effect of austempering parameters on microstructure and mechanical properties of horizontal continuous casting ductile iron dense bars 被引量:7
9
作者 Chun-jie Xu Pan Dai +3 位作者 Zheng-yang Zhang Zhong-ming Zhang Jin-cheng Wang Yong-hui Liu 《China Foundry》 SCIE CAS 2015年第2期104-110,共7页
In the present research, the orthogonal experiment was carried out to investigate the influence of different austempering process parameters (i.e. austenitizing temperature and time, and austempering temperature and ... In the present research, the orthogonal experiment was carried out to investigate the influence of different austempering process parameters (i.e. austenitizing temperature and time, and austempering temperature and time) on microstructure and mechanical properties of LZQT500-7 ductile iron dense bars with 172 mm in diameter which were produced by horizontal continuous casting (HCC). The results show that the major factors influencing the hardness of austempered ductile iron (ADI) are austenitizing temperature and austempering temperature. The fraction of retained austenite increases as the austenitizing and austempering temperatures increase. When austenitizing temperature is low, acicular ferrite and retained austenite can be efifciently obtained by appropriately extending the austenitizing time. The proper austmepering time could ensure enough stability of retained austenite and prevent high carbon austenite decomposition. The optimal mechanical properties of ADI can be achieved with the fol owing process parameters: austenitizing temperature and time are 866 &#176;C and 135 min, and austempering temperature and time are 279 &#176;C and 135 min, respectively. The microstructure of ADI under the optimal austempering process consists of ifne acicular ferrite and a smal amount of retained austenite, and the hardness, tensile strength, yield strength, elongation and impact toughness of the bars are HBW 476, 1670 MPa, 1428 MPa, 2.93%and 25.7 J, respectively. 展开更多
关键词 horizontal continuous casting (HCC) ductile iron dense bars austempered ductile iron (ADI) microstructure and mechanical properties orthogonal test
下载PDF
Effect of V and Nb additions on microstructure,properties,and deformability of Ti-45Al-9 (V,Nb,Y) alloy 被引量:3
10
作者 Yang Fei Kong Fantao +1 位作者 Chen Yuyong Xiao Shulong 《China Foundry》 SCIE CAS 2010年第4期357-361,共5页
Ti-45Al-9(V, Nb, Y) alloys with four different x=V/Nb (atomic ratio x = 1, 1.5, 2 and 3.5) have been prepared, and the microstructures, properties and hot deformation behaviors were investigated. SEM, XRD and TEM resu... Ti-45Al-9(V, Nb, Y) alloys with four different x=V/Nb (atomic ratio x = 1, 1.5, 2 and 3.5) have been prepared, and the microstructures, properties and hot deformation behaviors were investigated. SEM, XRD and TEM results showed that Ti-45Al-9(V, Nb, Y) alloys were mainly composed of γ, α 2 , and β phase, and the volume fraction of β phase increased with the increase of the atomic ratio of V/Nb. The alloys were featured with lamellar microstructure with β and γ phases locating at the colony boundaries, and some β precipitates appearing at γ/γ interfaces. It was found that the colony size decreased with the increase of x. The alloys exhibited moderate mechanical properties at room temperature, with a yield strength of over 600 MPa, and fractures showed mainly translamellar character. The alloy with x=3.5 exhibited the best deformability at elevated temperature and that with x=1 had superior oxidation resistance at 800 ℃. 展开更多
关键词 TiAl alloy microstructure and properties hot deformation behavior oxidation
下载PDF
Mechanical Properties and Microstructure of Portland Cement Concrete Prepared with Coral Reef Sand 被引量:22
11
作者 王乾坤 LI Peng +2 位作者 田亚坡 CHEN Wei SU Chunyi 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第5期996-1001,共6页
The feasibility of using coral reef sand(CRS) in Portland cement concrete is investigated by testing the mechanical property and microstructure of concrete. The composition, structure and properties of the CRS are a... The feasibility of using coral reef sand(CRS) in Portland cement concrete is investigated by testing the mechanical property and microstructure of concrete. The composition, structure and properties of the CRS are analyzed. Mechanical properties and microstructure of concrete with CRS are studied and compared to concrete with natural river sand. The relationship between the microstructure and performance of CRS concrete is established. The CRS has a porous surface with high water intake capacity, which contributes to the mechanical properties of concrete. The interfacial transition zone between the cement paste and CRS is densified compared to normal concrete with river sand. Hydration products form in the pore space of CRS and interlock with the matrix of cement paste, which increases the strength. The total porosity of concrete prepared with CRS is higher than that with natural sand. The main difference in pore size distribution is the fraction of fine pores in the range of 100 nm. 展开更多
关键词 coral reef sand concrete mechanical properties microstructure interfacial transition zone
下载PDF
Influence of SiO_2 nano-particles on microstructures and properties of Ni-W-P/CeO_2-SiO_2 composites prepared by pulse electrodeposition 被引量:2
12
作者 王军丽 徐瑞东 章俞之 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第5期839-843,共5页
Ni-W-P base composites containing CeO2 and SiO2 nano-particles were prepared on common carbon steel surface by pulse co-deposition of Ni,W,P,CeO2 and SiO2 nano-particles.The influence of SiO2 concentrations in bath on... Ni-W-P base composites containing CeO2 and SiO2 nano-particles were prepared on common carbon steel surface by pulse co-deposition of Ni,W,P,CeO2 and SiO2 nano-particles.The influence of SiO2 concentrations in bath on microstructures and properties of Ni-W-P/CeO2-SiO2 composites was studied,and the characteristics were assessed by chemical compositions,element distribution,surface morphologies,deposition rate and microhardness.The results indicate that when SiO2 concentration in bath is controlled at 20 g/L,the composites possess the fastest deposition rate,the highest microhardness,compact microstructures,smaller crystallite sizes and uniform distribution of W,P,Ce and Si within Ni-W-P matrix metal.Increasing SiO2 concentration in bath from 10 to 20 g/L leads to the refinement in grain size and the inhomogeneity of microstructures.While when SiO2 concentration is increased to 30 g/L,the crystallite sizes increase again and some bosses with nodulation shape appear on the surface of composites. 展开更多
关键词 pulse electrodeposition NANO-PARTICLE composite microstructure and property
下载PDF
Effects of Dysprosium Oxide Doping on Microstructure and Properties of Barium Titanate Ceramic 被引量:2
13
作者 蒲永平 任慧君 +1 位作者 陈维 陈寿田 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第4期442-445,共4页
Different amounts of dysprosium oxide were incorporated into barium titanate powders synthesized by hydrothermal method. Relations of substitution behaviors and lattice parameters with solid-solubility were studied. F... Different amounts of dysprosium oxide were incorporated into barium titanate powders synthesized by hydrothermal method. Relations of substitution behaviors and lattice parameters with solid-solubility were studied. Furthermore, the influences of dysprosium oxide doping fraction on grain size and dielectric properties of barium titanate ceramic, including dielectric constant and breakdown electric field strength , were investigated via scanning electron microscope, X-ray diffraction and electric property tester. The results show that dysprosium oxide can restrain abnormal grain growth during sintering and that fine-grained and high density of barium titanate ceramic can result in excellent dielectric properties. As mass fraction of dysprosium oxide is 0.6%, the lattice parameters of grain increase to the maximum because of the lowest vacancy concentration. The electric property parameters are cited as following: dielectric constant (25 ℃ ) reaches 4100, the change in relative dielectric constant with temperature is - 10% to 10% within the range of - 15 - 100 ℃, breakdown electric field strength (alternating current) achieves 3.2 kV·mm^-1, which can be used in manufacturing high voltage ceramic capacitors 展开更多
关键词 inorganic nonmetallic material dysprosium oxide doping microstructure and properties barium titanate ceramic rare earths
下载PDF
Production,Properties and Microstructures of Mg-RE-Zn-Zr(RE=MM,Nd) Alloy 被引量:2
14
作者 Kun YU, Wenxian LI and Songrui LICollege of Materials Science and Engineering, Central South University, Changsha 410083, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2002年第4期378-380,共3页
The Mg-MM and Mg-Nd master alloys were prepared through the ingot metallurgy method under the protection of a special flux. The thermodynamic behaviors of different rare earth elements in the molten Mg alloys were inv... The Mg-MM and Mg-Nd master alloys were prepared through the ingot metallurgy method under the protection of a special flux. The thermodynamic behaviors of different rare earth elements in the molten Mg alloys were investigated. Two experimental alloys, Mg-3.0 wt pct MM-0.7 wt pct Zn-0.7 wt pct Zr and Mg-2.8 wt pct Nd-0.7 wt pct Zn-0.7 wt pct Zr, were prepared. The hardness and tensile properties of experimental alloys were measured and the microstructures were observed. The results showed that the rare earth elements could react greatly with the Mg chloride in the flux. The Mg-Nd-Zn-Zr alloy displayed a good aging hardening effect. The dispersed metastable phase ? (Mg3Nd) is an important strengthening phase to improve the tensile properties of this alloy. So the Mg-Nd-Zn-Zr alloy has better tensile properties and elongation than those of the Mg-MM-Zn-Zr alloy, and the ductile fracture character could be observed. The microvoid coalescence is the dominant fracture mechanism in this alloy. 展开更多
关键词 Mg-RE-Zn-Zr alloy Rare earth microstructures and properties
下载PDF
Effect of extrusion on the microstructure and mechanical properties of a low-alloyed Mg-2Zn-0.8Sr-0.2Ca matrix composite reinforced by TiC nano-particles 被引量:2
15
作者 Zedong Wang Kaibo Nie +1 位作者 Kunkun Deng Jungang Han 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2022年第11期1981-1990,共10页
A low-alloyed Mg-2Zn-0.8Sr-0.2Ca matrix composite reinforced by TiC nano-particles was successfully prepared by semi-solid stirring under the assistance of ultrasonic,and then the as-cast composite was hot extruded.Th... A low-alloyed Mg-2Zn-0.8Sr-0.2Ca matrix composite reinforced by TiC nano-particles was successfully prepared by semi-solid stirring under the assistance of ultrasonic,and then the as-cast composite was hot extruded.The results indicated that the volume fraction of dynamical recrystallization and the recrystallized grain size have a certain decline at lower extrusion temperature or rate.The finest grain size of~0.30μm is obtained in the sample extruded at 200℃ and 0.1 mm/s.The as-extruded sample displays a strong basal texture intensity,and the basal texture intensity increases to 5.937 mud while the extrusion temperature increases from 200 to 240℃.The ultra-high mechanical properties(ultimate tensile strength of 480.2 MPa,yield strength of 462 MPa)are obtained after extrusion at 200℃ with a rate of 0.1 mm/s.Among all strengthening mechanisms for the present composite,the grain refinement contributes the most to the increase in strength.A mixture of cleavage facets and dimples were observed in the fracture surfaces of three as-extruded nanocomposites,which explain a mix of brittle-ductile fracture way of the samples. 展开更多
关键词 magnesium matrix composite EXTRUSION microstructure and mechanical properties TEXTURE FRACTURE
下载PDF
Effect of Trace Sc and Zr on the Mechanical Properties and Microstructure of A1 Alloy 2618 被引量:6
16
作者 Kun YU, Songrui LI and Wenxian LI (Department of Materials Science and Engineering, Central South University of Technology, Changsha 410083, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2000年第4期416-420,共5页
An experimental 2618(Al-Cu-Mg-Fe-Ni) alloy added with trace Sc and Zr was prepared by ingot metallurgy (IM) method. The aging behavior of the alloy was studied by Vickers hardness measurement at 200℃ and 300℃. and ... An experimental 2618(Al-Cu-Mg-Fe-Ni) alloy added with trace Sc and Zr was prepared by ingot metallurgy (IM) method. The aging behavior of the alloy was studied by Vickers hardness measurement at 200℃ and 300℃. and the tensile properties of alloy specimens were measured at 20℃, 200℃, 250℃ and 300℃. The microstructure was observed by using optical microscope, SEM and TEM. It was found that the addition of Sc and Zr to 2618 alloy resulted in a primary Al_3(Sc,Zr) phase which could refine the grain because it acts as nuclei of heterogeneous crystallization in the melt during solidification. The secondary Al_3(Sc,Zr) particles were full coherent with matrix and had obvious precipitation hardening effect. They also made the S' phase precipitate more homogeneous. So the strength of alloy increases at both ambient and elevated temperatures without a decrease of ductility. The ductile fracture of alloy occurs by microvoid nucleation, growth and coalescence, so the microvoid coalescence is the dominant fracture mechanism. 展开更多
关键词 Sc ZR Effect of Trace Sc and Zr on the Mechanical properties and microstructure of A1 Alloy 2618
下载PDF
Evolution of microstructure and mechanical properties of A356 aluminium alloy processed by hot spinning process 被引量:9
17
作者 Xiao-yan Wu Hua-rui Zhang +2 位作者 Huan-liang Chen Li-na Jia Hu Zhang 《China Foundry》 SCIE 2017年第2期138-144,共7页
The evolution of microstructure and mechanical properties of A356 aluminum alloy subjected to hot spinning process has been investigated. The results indicated that the deformation process homogenized microstructure a... The evolution of microstructure and mechanical properties of A356 aluminum alloy subjected to hot spinning process has been investigated. The results indicated that the deformation process homogenized microstructure and improved mechanical properties of the A356 aluminum alloy. During the hot spinning process, eutectic Si particles and Fe-rich phases were fragmented, and porosities were eliminated. In addition, recrystallization of Al matrix and precipitation of Al Si Ti phases occurred. The mechanical property testing results indicated that there was a significant increase of ductility and a decrease of average microhardness in deformed alloy over die-cast alloy. This is attributed to uniform distribution of finer spherical eutectic Si particles, the elimination of casting defects and to the recrystallized finer grain structure. 展开更多
关键词 hot spinning process A356 aluminum alloy microstructure mechanical properties
下载PDF
Microstructures and Properties of 550 MPa Grade High Strength Thin-walled H-beam Steel 被引量:2
18
作者 CHEN Jiping KANG Yonglin +2 位作者 QIAN Jianqing LI Shengzhi QIAN Haifan 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2013年第6期1217-1222,共6页
The microstructures and mechanical properties of 550 MPa grade lightweight high strength thin-walled H-beam steel were experimentally studied. The experimental results show that the microstructure of the air-cooled H-... The microstructures and mechanical properties of 550 MPa grade lightweight high strength thin-walled H-beam steel were experimentally studied. The experimental results show that the microstructure of the air-cooled H-beam steel sample is consisted of ferrite, pearlite and a small amount of granular bainites as well as fine and dispersive V(C,N) precipitates. The microstructure of the water-cooled steel sample is consisted of ferrite and bainite as well as a small amount of fine pearlites. The microstructure of the water-cooled sample is finer than that of the air-cooled sample with the average intercept size of the surface grains reaching to 3.5 gna. The finish rolling temperature of the thin-walled high strength H-beam steel is in the range of 750 ~C-850 ~C. The lower the finish rolling temperature and the faster the cooling rate, the finer the ferrite grains, the volume fraction of bainite is increased through water cooling process. Grain refinement strengthening and precipitation strengthening are used as major strengthening means to develop 550 MPa grade lightweight high strength thin- walled H-beam steel. Vanadium partially soluted in the matrix and contributes to the solution strengthening. The 550 MPa grade high-strength thin-walled H-beam steel could be developed by direct air cooling after hot rolling to fully meet the requirements of the target properties. 展开更多
关键词 H-beam steel high strength thin-walled vanadium-nitrogen microalloying microstructure and mechanical property strengthening mechanism
下载PDF
Microstructure and Mechanical Properties of Si_3N_4 Composites Containing SiC Platelet 被引量:3
19
作者 Tao WEI Yu ZHOU Tingquan LEI and Yujin WANG (School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1998年第2期151-155,共5页
Hoppressed Si3N4/SiC platelet composites had been investigated with respect to their microstructure and mechanical properties. The results indicate that Vickers hardness, elastic modulus and fracture toughness of the ... Hoppressed Si3N4/SiC platelet composites had been investigated with respect to their microstructure and mechanical properties. The results indicate that Vickers hardness, elastic modulus and fracture toughness of the composites were increased by the addition of SiC platelet until the content up to 20 vol pct. A slight decrease in flexural Strength was measured at room temperature with increasing SiC platelet content. The high temperature flexural strength tests at 1150, 1250, and 1350℃ were conducted. It was found that the flexural strength at elevated temperature was degraded with the rising temperature, and the downward trend of flexural strength for the composite containing 10 vol. pct SiC platelet was less. The results indicate that SiC platelet had a positive influence on the high temperature strength. Effects of SiC platelet reinforcement were presented 展开更多
关键词 SIC microstructure and Mechanical properties of Si3N4 Composites Containing SiC Platelet MPA
下载PDF
Effects of sphere size on the microstructure and mechanical properties of ductile iron–steel hollow sphere syntactic foams 被引量:5
20
作者 Hamid Sazegaran Ali-Reza Kiani-Rashid Jalil Vahdati Khaki 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2016年第6期676-682,共7页
The effects of sphere size on the microstructural and mechanical properties of ductile iron–steel hollow sphere(DI–SHS) syntactic foams were investigated in this study. The SHSs were manufactured by fluidized-bed ... The effects of sphere size on the microstructural and mechanical properties of ductile iron–steel hollow sphere(DI–SHS) syntactic foams were investigated in this study. The SHSs were manufactured by fluidized-bed coating via the Fe-based commercial powder–binder suspension onto expanded polystyrene spheres(EPSs). Afterwards, the DI–SHS syntactic foams were produced via a sand-mold casting process. The microstructures of specimens were investigated by optical microscopy, scanning electron microscopy(SEM), and energy-dispersive X-ray spectroscopy(EDS). The microscopic evaluations of specimens reveal distinct regions composed of the DI matrix, SHS shells, and compatible interface. As a result, the microstructures and graphite morphologies of the DI matrix depend on sphere size. When the sphere size decreases, the area fractions of cementite and graphite phases are observed to increase and decrease, respectively. Compression tests were subsequently conducted at ambient temperature on the DI–SHS syntactic foams. The results reveal that the compression behavior of the syntactic foams is enhanced with increasing sphere size. Furthermore, the compressed specimens demonstrate that microcracks start and grow from the interface region. 展开更多
关键词 ductile iron steel syntactic foams microstructure mechanical properties
下载PDF
上一页 1 2 10 下一页 到第
使用帮助 返回顶部