分散镶铸高锰钢复合材料组织与性能分析

采用分散镶铸工艺在高锰钢铸件内镶铸多状弹簧钢丝骨架，浇注后得到了复合材料试棒。在实验室采用金相、硬度试验、电子探针等手段对复合材料铸态及水韧处理后的组织、性能、元素扩散等进行了分析，并进行了耐磨性试验。金相分析结果表明：分散镶铸后，６５Ｍｎ钢丝在高锰钢铸件内部产生了良好的冶金结合，水韧处理后形成了网状纤维马氏体组织，从而提高高锰钢件在低冲击磨料磨损条件下的耐磨性，电子探针分析结果显示了锰元素在复合     

水韧处理对TiC基高锰钢结合金组织与性能的影响

系统研究了水韧处理对TiC基高锰钢结合金力学性能的影响,并通过分析合金在处理前后显微组织结构和微区成分的变化阐述了其中的内在关系.经过1 050℃×6h水韧处理后,真空烧结试样的抗弯强度和冲击韧性分别提高154.6%和125.3%;对低压烧结试样则分别提高61.81%和45.38%;对真空烧结+低压烧结试样也分别提高65.59%和32.90%.研究结果表明,水韧处理能够显著提高烧结态TiC基高锰钢结合金的抗弯强度和冲击韧性.因此,对烧结态TiC基钢结合金进行水韧处理或者高温成分均匀化热处理十分必要,有利于充分发挥其性能潜力.     

水韧处理对TiC基高锰钢结合金组织与性能的影响

研究了水韧处理对TiC基高锰钢结合金力学性能的影响,并通过分析合金在处理前后显微组织结构和微区成分的变化,阐述了其中的内在关系.经过1 050℃×6h水韧处理后,真空烧结试样的抗弯强度和冲击韧性分别提高了154.6%和125.3%;低压烧结试样则分别提高了61.81%和45.38%;真空烧结+低压烧结试样也分别提高了65.59%和32.90%.研究结果表明,水韧处理能够显著提高烧结态TiC基高锰钢结合金的抗弯强度和冲击韧性.     

热处理对ZGMn18Cr2MoRE组织和性能的影响

研究了热处理工艺对超高锰钢ZGMn18Cr2MoRE组织和力学性能的影响。试验结果表明,热处理工艺对超高锰钢组织和性能有显著影响,沉淀(弥散)强化使奥氏体晶内析出了弥散颗粒状M7C3型碳化物,强化了基体,使钢的力学性能得到提高。其中,经1100℃水韧处理后再经250℃×4h回火,ZGMn18Cr2MoRE钢的奥氏体晶粒细小,晶内颗粒状碳化物均匀、弥散分布,σb=994.51Mpa,sσ=430.98Mpa,αk=260J.cm-2,HB=227,δ=55.03%。与水韧处理后不回火相比,σb、sσ、αk、δ、HB分别提高了18.2%、7%、22%、30.3%、9.7%。     

热处理工艺对新型高锰钢组织和性能的影响

研究了热处理工艺对Cr、Mo、Ti、Al、Ca、RE新型高锰钢组织和力学性能的影响.试验结果表明,热处理工艺对新型高锰钢组织和力学性能有显著影响.低温等温预处理温度为580 ℃,保温3 h;高温水韧处理加热温度为 1 040～1 050 ℃, 保温3 h.可以改善高锰钢金相组织和力学性能,使σb=954 MPa , σs=507 Mpa,δ=46.8%,αK=338 J/cm2,HBS219.新型高锰钢履带板装车寿命考核结果,使用寿命由原来的3 200 Km提高到7 000 Km以上,取得了明显的经济效益.     

低稳定性奥氏体锰钢的形变强化浅析

高锰钢是目前广泛使用的一种耐磨钢。它是利用“水韧处理”(即将高锰钢加热至临界温度以上,一般为900～950℃,保温一段时间,得均匀奥氏体组织后,将钢迅速淬入水中冷却的处理)而获得奥氏体组织,在使用过程中,当其受到外界强大冲击力或压力时,奥氏体组织会产生     

稀土在高锰钢中的应用

近年来，许多行业对高锰钢的需求量急剧增加，不少企业开发了这一产品。然而由于缺乏生产高锰钢铸件的实际经验和必要的理论知识而遇到了不少困难。鉴于此，本文就稀土改善高锰钢机械性能的机理、稀土在高锰钢铸件生产中的使用效果和生产高锰钢铸件的工艺等问题进行了详细的叙述。     

挤压铸造对ZL201性能组织的影响

以铸造铝合金ZL201为研究对象,系统研究了挤压铸造成形工艺条件下,挤压压力、浇注温度、模具温度等工艺参数对合金显微组织和力学性能的影响。实验结果表明,ZL201的挤压铸造组织细密均匀,且随着挤压压力的增大,铸件的组织越加细密;结合实验结果,确定了ZL201合适的挤压工艺参数：浇注温度750℃、挤压压力60MPa、模具温度保持在250℃左右。在合适的工艺条件下,铸件的组织和性能良好,经过T4热处理后,铸件本体试样的抗拉强度和延伸率可以达到310MPa和9.27%。     

高锰钢环锤的节能固溶工艺研究

针对高锰钢环锤使用过程中出现裂纹、断裂、耐磨性差等缺陷,通过改进环锤消失模铸造工艺和利用铸造余热进行节能固溶处理来提高环锤的机械性能.研究结果表明:环锤浇注后,控制铸件在1 180℃出箱,经节能固溶处理,铸态的硬度为HB≥205,冲击韧性αk达197 J·cm-2,可满足产品使用性能要求.这一生产工艺大幅度缩短了生产周期,节约了生产成本,具有明显的市场竞争优势.     

钨和稀土对铸态高锰钢夹杂物和组织的影响

高锰钢铸件的质量、组织和力学性能是确保制件综合性能的基础和关键环节,而控制夹杂物和晶粒细化是行之有效的方法。采用添加1%W和0.3%RE对传统高锰钢进行微元合金化变质处理,研究了W和RE对夹杂物的形成、形态与分布的影响,揭示了改性高锰钢铸件晶粒细化的机理。结果表明:在凝固过程中先析出的W_2C可作为异质核心促进钢液非均匀形核,铸态组织明显改善;RE净化了钢液,夹杂物的数量减少,呈聚集态弥散分布,改善了制件的热脆性。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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