共查询到14条相似文献,搜索用时 0 毫秒
1.
J. Jiang H. Fu L. Zheng G. Shu‐Qi M. Yue L. Yong‐ping 《Materialwissenschaft und Werkstofftechnik》2016,47(9):822-830
Cast Fe–10Cr–1.5B–2Al alloy was quenched at different temperatures. The effects of quenching temperature on microstructure and hardness and wear‐resistance of Fe–10Cr–1.5B–2.0Al alloy were investigated by means of the optical microscopy, the scanning electron microscope, X‐ray diffraction, energy dispersive spectrometer, Vickers hardness and Rockwell hardness tester, and the MM‐200 block‐on‐ring wear testing machine under dry friction condition. The results indicate that the as‐cast microstructure of Fe–10Cr–1.5B–2.0Al alloy consists of ferrite, pearlite and netlike eutectics which are distributed in the grain boundary. The eutectics mainly include herringbone M2B and chrysanthemum M7(C, B)3. The matrix gradually turns into single martensite with the increase of the quenching temperature. The type of borocarbides has no obvious change after quenching. The netlike boride almost totally fractures and transforms from the fish‐bone structure to the graininess. There is some retained austenite in the quenched structures when the quenching temperature is more than 1100 °C. When the quenching temperature is in a range of 1000 °C to 1100 °C, the hardness and wear resistance show a sharp increase with an increase of temperature, and show a slight decrease after surpassing 1100 °C. 相似文献
2.
H. Zhang H. Fu Y. Jiang Z. Yu H. Guo Y. Lei R. Zhou Q. Cen 《Materialwissenschaft und Werkstofftechnik》2012,43(11):931-941
In this article, the effect of heat treatment in different quenching temperature on microstructure and hardness of Fe‐Cr‐B alloy was studied, by contrast with boron‐free Fe‐Cr alloy. The results indicated that microstructure of boron‐free Fe‐Cr alloy consisted of the martensite and a few (Cr, Fe)7C3 type carbide. The microstructures had no obvious change with the increase of quenching temperature, but its hardness increased from 51.5 HRC to 60.8 HRC. When boron element was added into the Fe‐Cr alloy, the netlike eutectic structure began to break and spheroidizing after quenching, in which the borocarbide turned into spherical groups and network Fe2B phase was broken. Moreover, the portion of martensite increased, and the amount of secondary carbide decreased, and the size of secondary carbide began to largen after quenching. When the quenching temperature reached 1100°C, secondary carbide particles dissolved in the matrix wholly. The hardness of Fe‐Cr‐B alloy increased with the increase of quenching temperature below 1050°C. The hardness of sample containing 2.0% B and quenching at 1050°C reached 66.7 HRC. The hardness of Fe‐Cr‐B alloy had no obvious change when quenching temperature continued to increase. After tempered at 200°C, the microstructure of Fe‐Cr‐B alloy had no significant change and its hardness had slight decrease. The hardness of sample containing 2.0% B tempered at 200°C reached 63.9 HRC. 相似文献
3.
Z. Yu H. Fu Y. Jiang Q. Cen Y. Lei R. Zhou H. Guo 《Materialwissenschaft und Werkstofftechnik》2012,43(12):1080-1085
The microstructures and mechanical properties of eight kinds of Fe‐Cr‐B‐Al alloys containing X wt.%Al‐0.35 wt.%C‐10.0 wt.%Cr‐1.4 wt.%B‐0.6 wt.%Si‐0.8 wt.%Mn (X = 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0) were studied by means of optical microscopy (OM), scanning electron microscopy (SEM), X‐ray diffraction (XRD), Rockwell hardness and Vickers micro‐hardness testers. The results indicate that the as‐cast microstructure of aluminium‐free sample consists of the martensite, austenite and eutectic borocarbides, and the eutectic borocarbides are the mixture of (Fe, Cr)2B and (Cr, Fe)7(C, B)3, and its hardness reaches 65 HRC. When a small amount of aluminium element (Al ? 1.0 wt.%) is added, the phase composition has no significant change, and the hardness excels 65 HRC. When the concentration of aluminium reaches 1.5 wt.%, the matrix of Fe‐Cr‐B‐Al alloy becomes pearlite and δ‐ferrite, leading to a sharply decrease of the hardness. The proportion of ferrite goes up along with increasing aluminium concentration, and the hardness of Fe‐Cr‐B‐Al alloy has slight decrease. 相似文献
4.
Effect of boron concentration on solidification structure and hardness of Fe–B–C wear‐resistant alloy
下载免费PDF全文
![点击此处可从《Materialwissenschaft und Werkstofftechnik》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Fe–B–C wear‐resistant alloy, as a new type of iron‐based wear‐resistant materials, has drawn extensive attention of the researchers in materials at home and abroad. The boron concentration plays an important role in the microstructure and mechanical properties of Fe–B–C wear‐resistant alloy. In this paper, the solidification microstructure, volume fraction of eutectic, macro and micro hardness of Fe–B–C alloy are researched. The samples are measured by optical microscopy (OM), scanning electron microscopy (SEM), Rockwell‐hardness tester, Vickers‐hardness tester. Image processing software such as image‐pro and photoshop are used. The content of boron in experiment alloys are 1.0%, 1.5%, 2.0%, 2.5% and 3.0% respectively. As a result, the solidification microstructure of as‐cast Fe–B–C mainly consists of metallic matrix and eutectic structure. The eutectic phase is continuous netlike distribution along the grain boundary. As boron concentration increases, the volume fraction of borocarbide increases in the matrix, and the size is larger. The hardness of Fe–B–C also has a tendency to rise with the increase of boron concentration. 相似文献
5.
H. Zhang H. Fu Y. Jiang H. Guo Y. Lei R. Zhou Q. Cen 《Materialwissenschaft und Werkstofftechnik》2011,42(8):765-770
In this article, the effect of boron concentration (B = 0, 0.4, 0.8, 1.4 and 2.0 respectively) on the solidification microstructure and properties of Fe‐Cr‐B alloy containing 0.35% C, 10–12% Cr, 0.5–0.8% Si, and 0.7–1.0% Mn was studied by means of the optical microscope (OM), the scanning electron microscope (SEM), X‐ray diffraction (XRD), Rockwell hardness and Vickers hardness tester. The results indicate that the microstructure of boron‐free sample consists of the martensite, and its hardness reaches 59.2 HRC. When a small amount of boron element was added, the eutectic phase of network structure generated along the grain boundary. The amount of eutectic phase increases when the boron concentration increases. Moreover, the eutectic phase is the mixture of boride and boron carbide. The boride is Fe2B and the boron carbide is (Cr, Fe)7(C, B)3. Compared with boron‐free sample, the Rockwell hardness of the samples with different boron concentrations are all higher, above 62 HRC, and the hardness grow up with the increase of boron concentration. When the boron concentration reaches to 1.4%, the Rockwell hardness of the alloy is 65.7 HRC, which is the highest in this study. When the boron concentration rises to 2.0%, the hardness has no obvious change. 相似文献
6.
The effect of quenching temperature and cooling rate on the structures of cast Fe‐B‐C alloy containing 1.0wt.%B and 0.2wt.%C was researched. The results showed that, under the same quenching temperature, the microstructures of the metallic matrix are transformed from the mixture of the pearlite, ferrite and martensite to the martensite along with the increase of quenching cooling rate. Under the water cooling condition, excessively low or excessively high quenching temperature did not favor to obtain the single martensite matrix. In the Fe‐B‐C alloy, the stability of Fe2B was good. It still had not been dissolved while heating up to 1050oC. The dissolution of boride appeared heating at the high temperature. The higher the quenching temperature was, the more the boride dissolved obviously. Along with the dissolution of boride, the boride morphology changed from network to broken‐network and isolated shape. When the heating temperature was 1050oC, the boride transformed the isolated shape completely. Quenching at 950~1000oC, cast Fe‐B‐C alloy transformed into the compound structures of fine lath martensite and boride in the water cooling condition. 相似文献
7.
Al–8Fe–4Ce alloy is currently manufactured by consolidating the atomized powders. With the aim to reduce the cost, spray forming process was applied in manufacturing with misch metal as raw materials. Spray forming (SF) as well as casting were employed to prepare Al–8Fe–4RE alloy, followed by hot‐press to compact the samples. The mechanical properties of SFed and cast Al–8Fe–4RE alloys are characterized at a temperature of 350 °C. The results show that the Al3Fe phases contained in SF alloy is comparatively refined, forming needle‐shaped phases embedded in the Al matrix, and the SF alloy also showed lower degree of preferred orientation in (111) plane. Although both factors might explain the superior performance of the SF sample, the fracture appearance after tensile test at 350 °C shows that the contribution from crystallographic feature might be predominant. Spray forming is proved to be a very promising technique for manufacture of Al–Fe–Ce alloys of high strength at an elevated temperature. 相似文献
8.
Microstructures and mechanical properties of as‐cast titanium–zirconium–molybdenum ternary alloys
下载免费PDF全文
![点击此处可从《Materialwissenschaft und Werkstofftechnik》网站下载免费的PDF全文](/ch/ext_images/free.gif)
C.D. Yang S.P. Wang J.J. Shi C.H. Wang Z.M. Ren G.H. Cao 《Materialwissenschaft und Werkstofftechnik》2018,49(1):30-38
In this study titanium–zirconium–molybdenum alloys (Ti50Zr50)100‐xMox (xMo; x = 0 at.%, 1 at.%, 3 at.%, 5 at.% or 7 at.%) were investigated, focusing on the effect of molybdenum addition on their microstructures and mechanical properties. Transmission electron microscopy observations revealed that the binary Ti50Zr50 alloy was composed entirely of an acicular hexagonal structure of the α’ phase. When the molybdenum content was 1 at.%, the alloy was composed of β and ω phases. However, when 3 at.% or more molybdenum was added, only the equiaxed, retained β phase was observed. Tensile tests at room temperature indicated that the mechanical properties of the 1Mo alloy were inferior owing to the embrittlement effects of the ω phase and the difficulty of dislocation motion through the ω phase. Our research suggested that the 5Mo alloy had excellent ductility (16.5 %) as well as adequate strength (780 MPa). The improved mechanical properties were attributed to the enhanced stability of the β phase and the disappearance of the ω phase. 相似文献
9.
Microstructure and mechanical properties of an Al‐Si alloy reinforced by Al64Cu24Fe12 quasi‐crystalline particles
下载免费PDF全文
![点击此处可从《Materialwissenschaft und Werkstofftechnik》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In this work, aluminum‐silicon alloy reinforced with Al64Cu24Fe12 quasi‐crystalline particles have been prepared by a traditional casting method with proper heat treatment process. The microstructures of the composites were examined using optical microscopy, scanning, X‐ray and energy dispersive spectrometer. The results indicate that there was no quasi‐crystalline phase remained and a new phase‐β (Al65‐75Si13‐26Fe3‐10) phase formed, which may act as a new reinforcing phase. There are three primary phases in the final composite: eutectic silicon, β‐phase and the α‐aluminum phase. Also the changes of mechanical properties were studied by tensile test and Vickers hardness test. The test results demonstrate that the mechanical properties of the composite is remarkably improved by adding proper amount of quasi‐crystalline particles. After adding 7.70 vol.% quasi‐crystalline particles, the tensile strength and the hardness increased by 70 % and 62 % respectively. However, adding a big amount (10.09 vol.%) of particles to molten aluminum‐silicon alloy will cause the particles aggregation and adhesion, which resulted in the decrease of the mechanical properties. 相似文献
10.
Liu Yong Zhu Jingchuan Wang Yang Zhan Jiajun 《Materials Science and Engineering: A》2008,490(1-2):113-116
Hot compressive behaviors of Ti–6Al–2Zr–1Mo–1V alloy at 1073 K, as well as the evolution of microstructure during deformation process, were investigated in this paper. The results shows that flow stress increases up to a peak stress, then decease with increasing strain, and forms a stable stage at last. The grain size also shows an decrease at first and increase after a minimum value. Dislocations are observed to produce at the interface of α/β phase, and the phase interface and dislocation circle play an important role in impeding the movement of dislocation. As strain increase, micro-deformation bands with high-density dislocation are founded, and dynamic recrystallization occurs. 相似文献
11.
A. Razaghian M. Emamy A.A. Najimi S.H. Seyed Ebrahimi 《Materials Characterization》2009,60(11):1361-1369
The effect of strontium as a modifier on the microstructures and tensile properties of two castable particulate metal matrix composites has been studied. The particulate metal matrix composites had similar matrix alloy (A357) but different reinforcing fine particles (silicon carbide and alumina). Results showed that the addition of 0.03% strontium makes a modest improvement to the yield strength, ultimate tensile strength and elongation percentage values, and the scatter of these properties, but makes a significant improvement to minimum strength and elongation results. Microstructural examinations by scanning electron microscope and energy dispersive spectroscopy analysis of metal matrix composites showed segregation of strontium on both the silicon carbide and alumina particles. Further results showed that the addition of higher strontium levels contributes to the over-modification of the eutectic silicon and promotes the formation of an Al–Si–Sr intermetallic compound on the particle/matrix interface. 相似文献
12.
The autocatalytic nature of the electroless nickel‐based alloy coating process will inevitably produce H2 bubbles which may be left in electroless nickel‐based alloy coating. If the H2 cannot be removed and left in the coating, it can lead to its poor corrosion resistance due to hydrogen cracks. So, the post treatment is an essential step for electroless deposition process. In this paper, electroless Ni–P and Ni–W–P coatings with chromium‐free pretreatment and dehydrogenation post treatment have been successfully prepared on AZ91D magnesium alloy, and the corrosion behaviors of the two kind coating samples in NaCl solution, HCl solution, and H2SO4 solution have been investigated. Both the polarization test and immersion tests show that the electroless Ni–W–P coating has better corrosion resistance than that of electroless Ni–P coating. 相似文献
13.
The effect of the solution treatment onto the microstructure and mechanical properties of MAG pulsed welded joints from X2CrNiMoN22‐5‐3 Duplex stainless steels
下载免费PDF全文
![点击此处可从《Materialwissenschaft und Werkstofftechnik》网站下载免费的PDF全文](/ch/ext_images/free.gif)
I. Mitelea I.‐D. Utu S. D. Urlan C. M. Crăciunescu 《Materialwissenschaft und Werkstofftechnik》2017,48(11):1040-1048
The metallurgical behaviour by Duplex stainless steels welding is affected by reducing the austenite proportion in weld and in the area adjacent to the fusion line of the molten metal bath and also by the precipitation of nitrides Cr2N, carbides M23C6 and intermetallic phases, σ, χ, Laves. The modalities for obtaining a quantitative ratio of the two phases (Austenite/Ferrite) close to that of the base metal (~50 % Austenite and 50 % Ferrite) aims to adjust the chemical composition of the weld by selecting a filler material with a higher nickel content (the element which beside nitrogen promotes the austenite formation), the heat cycle control of the welding process and the application of a post‐welding solution treatment. The present paper explores the effect of such heat treatment on balance restoring between austenite and ferrite and the reduction of the alloying elements segregation phenomena. By optical and scanning electron microscopy examinations and also X‐ray diffraction analyses the microstructural changes induced by the applied treatment are highlighted and by impact toughness and static tensile tests is demonstrated the positive effect of the heat treatment onto the ensuring of the welded joints quality. 相似文献
14.
Fe60Co8Zr10Mo5W2B15块体非晶合金的形成及热处理对性能的影响研究 总被引:2,自引:0,他引:2
用铜模吸铸法获得直径为2mm的Fe60Co8Zr10Mo5W2B15和Fe60Co8Zr10Mo5W2B15块体非晶合金。采用X射线衍射(XRD)、示差扫描量热分析(DSC)、显微硬度及压缩实验等研究了非晶合金的结构、热稳定性及热处理前后的显微硬度与压缩性能。结果表明Nb的引入不利于非晶合金的形成;Fe60Co8Zr10Mo5W2B15非晶合金的显微硬度为1343HV0.2,抗压强度σbe为972.6MPa;在低于晶化起始温度的热处理,硬度稍有下降;但在高于晶化峰值温度的热处理,硬度值随时间变化先升高,后下降;在热处理时间相同的条件下,随着热处理温度的升高,合金的硬度升高,但压缩强度会明显下降。 相似文献