Al-Cu-Sn合金WAAM堆积体的组织与性能

Al-Cu合金ZL205A电弧熔丝增材制造堆积体具有良好的综合力学性能,但在增材过程中产生有毒的氧化镉。本论文以Sn替换Cd,通过金相、SEM、EDS、TEM及拉伸试验,考察堆积体的微观组织和力学性能,并与ZL205A合金堆积体进行对比。结果发现,Al-Cu-Sn合金堆积体表面平整,呈现出银白色光泽,Sn元素的烧损率为5.9%。WAAM Al-Cu-Sn合金堆积体直接堆积态晶粒细小、均匀,晶粒尺寸约为30μm,小于ZL205A合金堆积体的晶粒尺寸,主要析出相在晶内和晶界上均匀分布。T6热处理后,θ相完全固溶到Al基体中,在晶界上均匀分布着复熔T相和Sn与Al2Cu的细小共生相,TEM显示晶内弥散分布大量的θ,相。T6热处理后,Al-Cu-Sn合金的力学性能为：抗拉强度：493Mpa;屈服强度：434Mpa;延伸率：9.5%。该合金在WAAM过程中表现出了优异的性能,具有广泛的应用前景。     

Al-Cu-Sn合金WAAM堆积体的组织与性能（英文）

Al-Cu合金ZL205A电弧熔丝增材制造(WAAM)堆积体具有良好的综合力学性能,但在增材过程中产生有毒的氧化镉。本研究以Sn替换Cd,通过金相、SEM、EDS、TEM及拉伸试验,考察堆积体的微观组织和力学性能,并与ZL205A合金堆积体进行对比。结果发现,Al-Cu-Sn合金堆积体表面平整,呈现出银白色光泽,Sn元素的烧损率为5.9%。WAAM Al-Cu-Sn合金堆积体直接堆积态晶粒细小、均匀,晶粒尺寸约为30μm,小于ZL205A合金堆积体的晶粒尺寸,主要析出相在晶内和晶界上均匀分布。T6热处理后,θ相完全固溶到Al基体中,在晶界上均匀分布着复熔T相和Sn与Al_2Cu的细小共生相,TEM显示晶内弥散分布大量的θ′相。T6热处理后,Al-Cu-Sn合金的力学性能为:抗拉强度493MPa;屈服强度434MPa;延伸率9.5%。该合金在WAAM过程中表现出了优异的性能,具有广泛的应用前景。     

电弧增材制造(WAAM)ZL114A铝合金组织与性能的研究

采用金相显微镜、扫描电镜、电子万能试验机等分析测试手段,研究了电弧增材制造工艺方法对ZL114A铝合金组织与性能的影响。与传统铸造成形方法相比,铸态组织具有更小的枝晶间距、Si相细小分布均匀;化学成分可有效控制;T6热处理后,Si相球化充分,第二相弥散分布在α-Al基体上,力学性能显著提升,抗拉强度、屈服强度及延伸率分为360MPa、315MPa、7.5%,延伸率是砂型铸造试样的2.1倍,拉伸断口呈现韧性断裂特征。WAAM成形试样缺陷主要为小于30μm的气孔,经过热处理后气孔数量减少,尺寸有变大趋势。     

镁合金轮毂的铸造工艺与组织性能

分别采用金属型铸造、常规挤压铸造和流变挤压铸造法制备了轮毂用Mg-2.9Nd-0.18Zn-0.35Zr镁合金,对比分析了三种不同铸造工艺下铸态和T6态镁合金的显微组织和力学性能,探讨了镁合金的强化机理。结果表明,金属型铸造合金的组织为α-Mg和以鱼骨状形式存在于晶界处的Mg_(12)Nd共晶相,平均α-Mg相尺寸约51μm,常规挤压铸造和流变挤压铸造合金的α-Mg相尺寸和Mg_(12)Nd相相似,但是后者的α-Mg相更加细小;三种铸造工艺下镁合金的主要物相都为α-Mg和Mg_(12)Nd,金属型铸造合金中α-Mg的晶格常数要比常规挤压铸造和流变挤压铸造的小。三种铸造工艺下T6态镁合金基体中都析出了细小短棒状β'相,且T6态常规挤压铸造和流变挤压铸造镁合金中β'相的尺寸相对金属型铸造更大,而T6态流变挤压铸造镁合金中还发现了细小盘状β"相。铸态和T6态镁合金的抗拉强度和屈服强度为:流变挤压铸造常规挤压铸造金属型铸造;T6态常规挤压铸造和流变挤压铸造相对金属型铸造镁合金的强度提高主要来自细晶强化和析出强化,且流变挤压铸造的细晶强化和析出强化效果要优于常规挤压铸造。     

Al-Si-Mg-Y合金消失模铸造振动压力凝固的组织与性能

应用消失模铸造振动压力凝固成形技术制备了Al-7Si-0.8Mg-0.3Y(ASMY)合金。通过SEM、XRD、DSC和TEM等测试方法对其铸态和T6组织进行分析,研究其对力学性能的影响。结果表明:在ASMY合金铸态组织的晶界处生成有少量Al3Y短棒状颗粒相;在T6热处理过程中,稀土Y或Al3Y阻碍Mg2Si相的析出和扩散聚集,使析出相Mg2Si呈弥散分布;Mg2Si相与晶界稳定相Al3Y对合金同时起到钉扎强化作用;采用消失模铸造振动压力凝固技术后,铝合金的孔隙率显著降低,从1.1%降低0.18%;ASMY合金消失模铸造振动压力凝固试样T6态的抗拉强度达到308MPa,比A356普通消失模试样T6态的抗拉强度提高29%。     

铸造工艺对WE54镁合金显微组织和力学性能的影响

对比研究了金属型铸造和树脂砂铸造WE54合金的显微组织和力学性能。结果表明,金属型铸造和树脂砂铸造WE54合金具有相似的铸态组织,但是由于冷却速度较慢,树脂砂铸造WE54合金的显微组织更加粗大,铸态组织中第二相的含量较少。金属型铸造的力学性能优于树脂砂铸造WE54合金,两者在峰值时效(T6)状态下的抗拉强度分别为327 MPa和261 MPa,屈服强度分别为234 MPa和209 MPa。造成树脂砂铸造WE54合金强度较低的主要原因是晶粒尺寸更为粗大。此外,树脂砂铸造合金中存在的缩松缺陷也使得合金的抗拉强度降低。     

T6处理对 ZL105A 铸造铝合金组织和性能的影响

对ZL105A铸造铝合金进行了T6处理。研究了铸态和经T6处理后该合金的显微组织、力学性能和拉伸试样断口形貌。结果表明,T6处理后,ZL105A合金组织更细小、均匀,硬度、抗拉强度大幅度提高,断后伸长率降低。     

Cu含量对低频电磁铸造新型高强Al-Mg-Si-Cu合金组织性能的影响北大核心CSCD

采用显微组织观察、扫描电镜及能谱分析、透射电镜分析、DSC热差分析、JMat Pro 5.0软件计算和室温力学性能测试,对低频电磁铸造新型高强Al-Mg-Si-Cu合金铸态、挤压态和T6态的组织与力学性能进行研究,获得该合金的最佳Cu含量。结果表明,Cu含量的变化对该合金过烧温度影响很小,不同含Cu量的该类合金进行均匀化处理和固溶处理时温度可相同。Cu在该合金铸态组织中除了形成球状AlMgSiCu相外,含Cu相还可与其他相结合形成球状共晶组织。Cu对合金再结晶行为的影响很小。随Cu含量的增加,合金T6态试样中Q'析出强化相的数量增加,同时该合金挤压棒材T6态试样的强度和伸长率也增加。在限定的元素含量范围内,提高Cu含量至1.0 mass%,合金的强韧性可达到最佳状态。     

钇变质剂加入量对ZL114A合金组织和力学性能的影响

使用不同含量的钇对ZL114A合金进行了变质处理,并对使用金属型模具铸造的合金进行了T6处理,研究了钇变质剂加入量对ZL114A合金显微组织和力学性能的影响。结果表明,未变质时合金的硅相呈粗大的棒状,加入钇变质剂后,硅相的体积明显减小,圆整度提高,没有尖角存在,且T6热处理后绝大部分共晶硅由棒状变成颗粒状或球状,并且分布均匀。钇加入量为0.3%时铸态合金的力学性能最好,抗拉强度达到181 MPa,伸长率达到3.9%,与未变质合金相比,分别提高了15%、77%。经过综合考虑,钇的最佳加入量为0.3%。     

Cu含量对低频电磁铸造新型高强Al-Mg-Si-Cu合金组织性能的影响

采用显微组织观察、扫描电镜及能谱分析、透射电镜分析、DSC热差分析、JMat Pro 5.0软件计算和室温力学性能测试,对低频电磁铸造新型高强Al-Mg-Si-Cu合金铸态、挤压态和T6态的组织与力学性能进行研究,获得该合金的最佳Cu含量。结果表明,Cu含量的变化对该合金过烧温度影响很小,不同含Cu量的该类合金进行均匀化处理和固溶处理时温度可相同。Cu在该合金铸态组织中除了形成球状AlMgSiCu相外,含Cu相还可与其他相结合形成球状共晶组织。Cu对合金再结晶行为的影响很小。随Cu含量的增加,合金T6态试样中Q'析出强化相的数量增加,同时该合金挤压棒材T6态试样的强度和伸长率也增加。在限定的元素含量范围内,提高Cu含量至1.0 mass%,合金的强韧性可达到最佳状态。     

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.     

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.     

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.     

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.