内氧化法制备的Cu-Al2O3合金的显微组织与性能

利用内氧化法制备了Cu-Al2O3弥散强化铜合金,并对其挤压态、冷拉态、退火态棒材进行了性能测试和显微组织结构分析.结果表明挤压后的棒材经65%和90%的变形量冷拉拔后,存在明显的加工纤维组织,σb分别达468和495MPa,相对电导率分别为90%和89%IACS;1030℃×0.5h高温退火后再结晶现象并不明显,仍能保持较高的强度;且变形量越大,高温退火后强度下降越小;合金的拉伸断口表现为韧性与脆性的混合型断裂.     

中间退火对冷轧5052合金组织及力学性能的影响

对初始变形量为37.5%的5052铝合金冷轧板进行中间退火试验,研究了不同退火条件下5050合金组织和力学性能的影响规律。结果表明,随着中间退火温度的提高和退火时间的延长,合金组织由变形亚结构态逐渐转变为完全再结晶组织,再结晶晶粒尺寸的分布较均匀;经二次冷轧后,合金在400℃下退火时屈服强度σ0.2、抗拉强度σb和屈强比σ0.2/σb均较在350℃下的低,而伸长率δ5却比在350℃时高。     

5083铝合金冷拔及回复对强度、塑性的影响

5083铝镁合金冷作硬化较明显,经22％的冷变形后,它的强度b=39公斤/毫米~2,60.2=29.25公斤/毫米~2,而δ_(10)只有3～4％。这样的延伸率远远不能满足构件的需要。为了得到良好的综合性能,我们做了挤压后不退火冷拔,变形形量ε=22％,挤压后退火冷拔,变形量ε=22％,挤压后不退火冷拔再回复处理(回复是指变形金属在加热期内某些力学性能和晶内亚结构发生了变化,但新的再结晶晶粒尚未出现的退火过程),以及冷变形量ε=15％拉拔后不退火的拉力实验。结果见表1。     

GWN751K镁合金组织和性能研究

采用OM,SEM,TEM,XRD等手段,研究了不同状态的GWN751K镁合金的组织和性能。结果表明:铸态合金主要由基体和网状共晶组织构成,σb=215MPa,σ0.2=187MPa,δ=3.5%,DSC曲线存在明显的低熔点吸热峰;经过535℃,16h热处理,共晶组织分解,晶界残留富Mg-Y相,晶粒尺寸明显长大,合金的力学性能有所改善,σb=240MPa,σ0.2=189MPa,δ=10%,DSC曲线低熔点吸热峰消失;合金经过挤压后,发生动态再结晶,力学性能显著提高,σb=320MPa,σ0.2=260MPa,δ=18%,最主要的原因是挤压后合金中存在高密度位错以及细小的晶粒,可显著提高合金的强度和塑性;经过时效后,合金的平均断裂强度达到400MPa以上,但塑性明显降低。铸态合金二次裂纹主要存在于晶界的共晶组织中,535℃,16h热处理以及挤压后的合金二次裂纹主要是在晶粒内部。     

热处理对挤压Mg-5.5Zn-1.7Nd-0.7Cd-0.5Zr镁合金组织和性能的影响

采用光学显微镜及透射电镜研究了挤压变形Mg-5.5Zn-1.7Nd-0.7Cd-0.5Zr镁合金在不同热处理条件下的组织和性能。结果表明,经T6(固溶420℃×20h+时效200℃×20h)处理后,合金的抗拉强度和屈服强度低于挤压态,而经过T5(时效120℃×15h)处理后,高于挤压态;在T5工艺条件下,合金具有较好的力学性能,其抗拉强度σb=349MPa,屈服强度σ0.2=315MPa,伸长率δ=13%。     

Mg-6Zn-1Y-Zr镁合金的组织与性能研究

Mg-6Zn-1Y-Zr镁合金在热锻或热挤压过程中发生了动态再结晶.合金组织细化,但不均匀,平均晶粒尺寸约10 μm.挤压态材料经350℃×30 min再结晶退火转变为等轴细晶组织,平均晶粒尺寸已达到5μm左右.合金在变形处理后有新的第二相析出,且合金的力学性能有很大提高.其中锻态Mg-6Zn-1Y-Zr合金的σb达到265 MPa,σ0.2达155 MPa,挤压态合金的σb达到330 MPa,σ0.2达185MPa.     

热处理对Mg-Gd-Y-Zr合金组织和力学性能的影响

采用拉伸、硬度、显微组织观察等方法,研究了不同热处理条件对Mg-Gd-Y-Zr合金组织和力学性能的影响。结果表明,铸态Mg-Gd-Y-Zr合金经固溶处理后其塑性提高,δ5提高40%;挤压可以明显改善合金的强度和塑性,相比铸态,σb提高25%,σ0.2提高30%,δ5达到14.9%;时效可使挤压态合金的强度得到进一步提高,峰时效时,σb达到420MPa,σ0.2达到310MPa,但塑性有所降低,δ5降低至7.5%。     

内氧化-冷轧制备Al_2O_3弥散强化铜合金的组织与性能

以Cu-0.15%(质量分数)Al合金粉末为原料、Cu2O为氧化剂,采用内氧化-冷轧法制备Al2O3弥散强化铜合金,研究合金的组织与性能。结果表明:由内氧化-冷轧法制备的合金的σb520MPa、σ0.2/σb90%、电导率(IACS)也保持在80%以上;经950℃退火后,合金的σb400MPa;此合金具有高强、高导和优良的抗高温软化性能;冷轧态弥散强化铜合金的组织呈拉长变形的纤维状,试样断口分布有一定数量的韧窝;经950℃退火后,合金的纤维组织宽化,试样断口表面韧窝增多、变深,塑性提高。     

退火温度对Al-6Mg-Sc-Zr合金组织与性能的影响

采用半连续铸锭冶金法制备一种成分为Al-6Mg-0.4（Sc＋Zr）的合金,冷轧板材经不同温度稳定化退火处理1 h,然后测试合金的拉伸力学性能,借助光学金相、扫描电镜、能谱仪以及透射电镜分析研究不同退火温度下Al-6Mg-0.4（Sc＋Zr）合金的显微组织结构变化及微区成分。结果表明：合金抗拉强度和屈服强度随退火温度的升高而降低,而其伸长率随退火温度的升高而增大;合金在退火过程中,随退火温度的升高,依次发生不同程度的回复和部分再结晶;300℃以下退火1 h,合金中只发生不同程度的回复;350-500℃退火1 h,发生部分再结晶;合金在300℃退火处理1 h后拉伸力学性能为：σb 423 MPa,σ0.2 311 MPa,δ20.8%。     

高低温处理条件下AZ31镁合金的力学性能与微观组织

针对月球环境温度变化情形,研究了长时间低温浸泡(-196℃)和多次高低温交变循环处理(-196～200℃)对挤压态AZ31镁合金在20℃下的力学性能、显微组织以及断口形貌的影响.研究表明:AZ31镁合金经过长时间液氮浸泡和高低温交变循环处理后,力学性能无明显变化;室温态合金的σb和δ分别为288 MPa和18.3％,经过10 d低温浸泡后σb和δ分别为292 MPa和18.7％,经过10次高低温循环后合金的σb和δ分别为294 MPa和16.9％;低温和高低温交变处理对断口形貌和相组成没有明显影响,均为准解理断裂.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.