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The effects of RE (La and Ce) on toughness of 30CrMnSi wear-resistance cast steel have been investigated by means of analysing microstructures and mearsering the properties of the steel with and without RE. The results show that RE can refine the as-cast microstructures, hinder or eliminate needle and network ferrite, increase the dislocation density and the quantity of dislocated martensite, and improve the shape and distribution of inclusions. Therefore the mechanical properties of the steel can be greatly enhanced, especially the toughness of the steel. 相似文献
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H. Fu Dr. Y. Miao X. Chen K. Hu Z. Tian 《Materialwissenschaft und Werkstofftechnik》2007,38(3):233-238
The microstructure, tensile and impact behaviour of high‐carbon Si‐Cr cast steel containing rare earth (RE) and titanium have been determined after austempering. The additions of RE and titanium refined the primary austenite grain size resulting in improving toughness. The addition of silicon handicapped the formation of carbide and carbide‐free bainitic ferrite and carbon enriched retained austenite could be obtained in the austempering structures of high‐carbon Si‐Cr cast steel, which had excellent mechanical properties and abrasion resistance. Moreover, the basic tendency of the mechanical properties of high‐carbon Si‐Cr cast steel influenced by the austempering temperature was that the hardness and tensile strength reduced and the impact toughness and fracture toughness increased with increasing temperature. The comprehensive properties were the best while austempering at 330oC. 相似文献
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《材料科学技术学报》2019,35(7):1298-1308
High-carbon chromium bearing steels with different rare earth (RE) contents were prepared to investigate the effects of RE on inclusions and impact toughness by different techniques. The results showed that RE addition could modify irregular Al2O3 and MnS into regular RE inclusions. With the increase of RE content, the reaction sequence of RE and potential inclusion forming elements should be O, S, As, P and C successively. RE inclusions containing C might precipitate in molten steel and solid state, but the precipitation temperature was significantly higher than that of carbides in high-carbon chromium bearing steel. For experimental bearing steels, the volume fraction of inclusions increased steadily with the increase of RE content, but smaller and more dispersed inclusions could be obtained by 0.018% RE content compared with bearing steel without RE, whereas the continuous increase of RE content led to an increasing trend for inclusion size and a gradual deterioration for inclusion distribution. RE addition could improve the transverse impact toughness and isotropy of bearing steel, and for modified high-carbon chromium bearing steel by RE alloying, the increase of RE content continuously increased both transverse and longitudinal impact toughness until excessive RE addition. 相似文献
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Wenlong Xiao Yusen Shen Lidong Wang Yaoming Wu Zhanyi Cao Shusheng Jia Limin Wang 《Materials & Design》2010
The influences of rare earth (RE) on the microstructure and mechanical properties of Mg–7Zn–5Al alloy were studied. The results indicate that both the dendrite and grain size of the alloy can be refined by low RE addition. The Al2REZn2 phase will be formed with increasing the RE content, however the high RE addition results in the grain coarsening in the alloy due to the decrease of the contribution of Al and Zn solutes on the grain refinement. The strengthening and weakening mechanisms caused by RE addition only lead to the obviously improve on the room temperature ultimate tensile strength. The mechanical properties of the studied alloys can be improved by aging treatment, and the aged Mg–7Zn–5Al–2RE alloy exhibits optimal mechanical properties at room temperature. 相似文献
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Drahomír Dvorský Jiří Kubásek Ilona Voňavková Dalibor Vojtěch 《Materials Science & Technology》2019,35(5):520-529
Rare earth elements are known to improve both mechanical and corrosion properties. However, it highly depends on the final microstructure conditions of prepared material. During extrusion, intermetallic phases may be redistributed, partially dissolved or on the contrary, precipitated. The knowledge of the impact of extrusion on the individual alloys is therefore essential for their application. In this work, three magnesium alloys (Mg-4Y-3RE, Mg-2Y-1Zn, Mg-3Nd-0.5Zn) were prepared by an extrusion process. Microstructure, mechanical and corrosion properties were compared with extruded pure Mg. The advantages and disadvantages of individual alloys are discussed. Based on the obtained results, the Mg-4Y-3RE alloy seems to exert the best mechanical and corrosion properties. Other materials were characterised with anisotropy of mechanical properties and much higher corrosion rate. 相似文献
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Rare-earth additions to lead-free electronic solders 总被引:5,自引:0,他引:5
The research in lead(Pb)-free solder alloy has been a popular topic in recent years, and has led to commercially available
Pb-free alloys. Further research in certain properties to improve aspects such as manufacturability and long term reliability
in many Pb-free alloys are currently undertaken. It was found by researchers that popular Pb-free solders such as Sn–Ag, Sn–Cu,
Sn–Zn and Sn–Ag–Cu had improved their properties by doping with trace amounts of rare earth (RE) elements. The improvements
include better wettability, creep strength and tensile strength. In particular, the increase in creep rupture time in Sn–Ag–Cu–RE
was 7 times, when the RE elements were primarily Ce and La. Apart from these studies, other studies have also shown that the
addition of RE elements to existing Pb-free could make it solderable to substrates such as semiconductors and optical materials.
This paper summarizes the effect of RE elements on the microstructure, mechanical properties and wetting behavior of certain
Pb-free solder alloys. It also demonstrates that the addition of RE elements would improve the reliability of the interconnections
in electronic packaging. For example, when Pb-free-RE alloys were used as solder balls in a ball grid array (BGA) package,
the intermetallic compound layer thickness and the amount of interfacial reaction were reduced. 相似文献
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Mg–5Li–3Al–2Zn–xRE alloys were prepared. The microstructure and mechanical properties of as-cast and wrought specimens were studied. RE elements
in Mg–5Li–3Al–2Zn alloy cause the microstructure refinement and the formation of Al3La, which bring about the improvement of mechanical properties of alloys. The optimal RE content for Mg–5Li–3Al–2Zn alloy
is 2 wt%, which makes the microstructure the finest and the mechanical properties the best. The further increase of RE content
makes the microstructure be coarsened and the morphology of Al3La change from particular to rod-like and pearlite-like eutectic shape, leading to the poor mechanical properties of alloys. 相似文献
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Wei Qiu ) Enhou Han) Lu Liu) ) Environmental Corrosion Center Institute of Metal Research Chinese Academy of Sciences Shenyang China ) Shenyang National Laboratory for Material Science China 《材料科学技术学报》2009,25(3):356-360
In this work, the influence of element RE on the microstructures and mechanical properties of the hot extuded Mg-3Al-1Zn-xRE alloys (with element RE content of 0.05, 0.1 and 0.2 wt pct) has been investigated and compared.It was found that RE can bring about precipitations phase that is identified as Al11 RE3 by X-ray diffraction and transmission electron microscopy (TEM).The grain sizes would not be refined after adding RE element.Al11 RE3 phase would increase strength and decrease the ductility.The addition of RE element affects dynamic recrystallized process and even reorientation of recrystallized grains.The results showed that the mechanical properties of AZ31+RE alloy are affected by combination of Al atoms, Mn atoms, Al11RE3phase and grains orientation.It is important to consider the ratio of RE/Al when designing new Mg-Al-RE alloys. 相似文献
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《Materials Science & Technology》2013,29(8):1021-1024
AbstractThis paper deals with the effects of rare earth (RE) addition on the microstructure and properties of 20Cr2Ni4A steel carburised at 860°C. Compared with conventional 920°C carburising and other complex treatments, finer and more dispersed carbide precipitates formed in the surface layers. A superfine martensitic structure and a less residual austenite were obtained by direct quenching after RE 860°C carburising. The microstructure exhibited a higher microhardness, a wear resistant surface layer, and it also led to an increase in impact toughness. In addition, the heat treatment period for this steel was remarkably reduced by the replacement of conventional complex treatments by RE 860°C carburising. 相似文献
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Effect of rare-earth treatment on the banded microstructure and fracture properties of a 16 Mn steel 总被引:2,自引:0,他引:2
The two treatments, namely rare-earth (RE) additions to the mould and Ca-Si injection into the ladle, were used to control
the MnS inclusion shape in a 16 Mn steel. The critical crack opening displacement, δc, method and tensile testing were used to determine the fracture properties of the steel sheets. Scanning electron microscope
(SEM) fractography of the fracture surface of tensile specimens tested at room temperature clearly showed the banded structure
of the steel sheets in all, even modified, steels. The RE treatment improved the fracture properties both by sulphide inclusion
shape control and by reducing microstructural heterogeneity. 相似文献
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为取代钢领生产厂家现行的碳氮共渗工艺,采用"无毒液体C-N-RE共渗"对20钢制纺织钢领进行了共渗试验,对共渗试样的显微组织、截面显微硬度、渗层碳浓度和稀土元素浓度进行了测定和研究。结果表明,经"无毒液体C-N-RE共渗"淬火后,20钢制纺织钢领的表面碳浓度大大增加,显微硬度大大提高,显微组织主要包含碳氮化合物、针状马氏体和残余奥氏体,稀土元素起到了良好的催渗作用。 相似文献
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氧化物弥散强化钢(Oxide Dispersion Strengthened Steel, ODS钢),具有优异的力学性能、高温稳定性及抗辐照性能.本文概要地综述了机械合金化、热等静压固化成形、等离子烧结及转角挤压等ODS钢的制备方法,总结了微观组织及结构对ODS钢性能的影响规律及影响机制,又综述了合金元素对ODS钢性能影响的相关研究进展;并对ODS钢在核电领域中的应用及相关研究进展进行了概括,介绍了激光技术在ODS钢制备及加工领域的应用,讨论了ODS钢在核电环境服役过程中存在的主要问题及进一步的研究方向,为核电站的安全运行提供有力的参考依据,对于核电材料的创新发展具有一定的参考作用. 相似文献
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《Materials Science & Technology》2013,29(11):1020-1029
AbstractA transition metal joint between type 304 stainless steel and 2·25Cr–1Mo steel, with Alloy 800 as the transition piece, is being developed for application in the steam generator circuit of the 500 MW prototype fast breeder reactor. As part of this programme, the hot cracking susceptibility of Inconel 82/182 and of 16–8–2 welding consumables were compared and the microstructure and mechanical properties of butt welds between type 304 stainless steel and Alloy 800, welded by the two consumables, were studied to select the appropriate welding consumables for this joint. It is recommended that the 16–8–2 consumable should be used for welding this joint because of its lower microfissuring tendency and reduced mismatch in the coefficient of thermal expansion across the joint, although this would mean a slight adverse effect on the elevated temperature mechanical properties. Further, to select the optimum post-weld heat treatment (PWHT) of the joint between Alloy 800 and 2·25Cr–1Mo steel, welded with Inconel 82/182 welding consumables, the effect of PWHT on the microstructure and mechanical properties was studied. Decreasing the PWHT temperature was found to improve the mechanical properties and the microstructural condition of this joint.MST/842 相似文献
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根据公路桥梁用钢的应用特点和要求,通过制定合理的成分和冶炼、轧制工艺,采用C—Mn,Nb、Ti微合金化的成分体系及控轧工艺,开发出公路桥梁用高强度结构钢WQ540D。对该钢的冶金质量、微观组织、基本力学性能进行了分析。试验结果显示:该钢具有优良的综合力学性能,满足公路桥梁用高强度结构钢的技术和使用要求。 相似文献
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911 World Trade Centre Tragedy put fire safety of constructional steel structures into question. Since then, more and more research attention has been paid to the elevated-temperature mechanical properties of structural steels, which is a critical basis of evaluating the fire performance of steel structures. In the literature the available mechanical properties of structural steels under fire conditions were mainly obtained from steady state test method, as steady state test method is easier to perform than transient state test method and offers stress–strain curves directly. However, the transient state fire condition is considered to be more realistic to represent the real condition when constructions are exposed to fire. In order to reveal the deterioration of mechanical properties of the commonly used high strength structural steel S460N under transient state fire condition, tensile tests were conducted under various constant stress levels up to 800 MPa. The reduction factors of elastic modulus, yield and ultimate strengths of S460N under transient state fire condition were obtained and compared with current leading design standards and available literature. The application of such accurate elevated-temperature mechanical properties reduction factors of S460N can ensure a safe fire-resistance design and evaluation of steel structures with high strength steel S460N under transient state fire condition. This experimental study also supports other relative research on fire performance of steel structures with S460N under transient state fire condition. 相似文献
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Monika Cie?lik Marcin KotWitold Reczyński Klas EngvallWies?aw Rakowski Andrzej Kotarba 《Materials science & engineering. C, Materials for biological applications》2012,32(1):31-35
The mechanical and protective properties of parylene N and C coatings (2-20 μm) on stainless steel 316L implant materials were investigated. The coatings were characterized by scanning electron and confocal microscopes, microindentation and scratch tests, whereas their protective properties were evaluated in terms of quenching metal ion release from stainless steel to simulated body fluid (Hanks solution). The obtained results revealed that for parylene C coatings, the critical load for initial cracks is 3-5 times higher and the total metal ions release is reduced 3 times more efficiently compared to parylene N. It was thus concluded that parylene C exhibits superior mechanical and protective properties for application as a micrometer coating material for stainless steel implants. 相似文献