冷轧复合铝-铝-钢界面金属间化合物的生长行为

对冷轧复合4343铝/4A60铝/08Al钢三层复合带材进行不同温度和时间的退火,借助金相显微镜、扫描电镜和EDAX能谱仪以及X射线衍射仪对复合界面结合区进行组织观察、元素成分线扫描分析和EDS能谱分析及XRD物相分析,研究复合界面金属间化合物的生长行为。结果表明：当退火温度较高时,4343中含量较高的Si向4A60中进行了较大程度的扩散;铝-钢复合界面在600 ℃保持1 h退火时有金属间化合物产生;随着退火温度的升高和退火时间的延长,复合界面金属间化合物由一层增加至三层,化合物主要由Fe₄Al₁₃和Fe₂Al₅组成;铝-钢复合界面金属间化合物的生长由扩散控制,其增厚符合抛物线规律,界面金属间化合物的生长激活能为14.4 kJ/mol。     

预镀层不锈钢/铝异种金属高频感应钎焊接头界面及力学性能分析

文中通过热浸镀一层纯铝到不锈钢表面,再对0Cr18Ni9不锈钢和LF21铝合金采用高频感应钎焊.当热浸镀时间从10 s增加到50 s时,镀层厚度从7 μm增加到20 μm,反应层由FeAl₃向Fe₂Al₅发生转变.在热浸镀温度为750℃,浸镀时间为10 s时,镀层成型最好,高频感应电流为270 A,加热时间30 s时,抗拉强度达到167.12 MPa,比不浸镀的接头强度高63.8%.主要是因为镀层限制钢中的Fe原子和Al-Si钎料中的Al,Si原子的相互扩散,在热浸镀不锈钢与铝合金反应中使Fe₂Al₅转化为Fe（Al,Si）₂固溶体而未形成5-Al₈Fe₂Si化合物,降低了界面上硬脆化合物的含量,力学性能随之提高.     

表面活化Al2O3陶瓷与5005铝合金真空钎焊

采用Al-Si钎料对经过Ag-Cu-Ti粉末活性金属化处理的Al₂O₃陶瓷与5005铝合金进行了真空钎焊,研究了钎焊接头的典型界面组织,分析了钎焊温度对接头界面结构特征及力学性能的影响. 结果表明,接头典型界面结构为5005铝合金/α-Al+θ-Al₂Cu+ξ-Ag₂Al/ξ-Ag₂Al+θ-Al₂Cu+Al₃Ti/Ti₃Cu₃O/Al₂O₃陶瓷. 钎焊过程中,Al-Si钎料与活性元素Ti及铝合金母材发生冶金反应,实现对两侧母材的连接. 随着钎焊温度的升高,陶瓷侧Ti₃Cu₃O活化反应层的厚度逐渐变薄,溶解进钎缝中的Ag和Cu与Al反应加剧,生成ξ-Ag₂Al+θ-Al₂Cu金属间化合物的数量增多,铝合金的晶间渗入明显;随钎焊温度的升高,接头抗剪强度先增加后降低,当钎焊温度为610 ℃时,接头强度最高达到15 MPa.     

钎料中Ti元素含量对Si3N4/Si3N4接头界面结构及性能的影响

在900℃保温10 min的工艺条件下采用Ti含量不同的AgCu+Ti+nano-Si₃N₄复合钎料（AgCu_C）实现了Si₃N₄陶瓷自身的钎焊连接,并对不同Ti元素含量的接头界面组织及性能进行了分析.结果表明,接头典型界面结构为Si₃N₄/TiN+Ti₅Si₃/Ag_（s,s）+Cu_（s,s）+TiN_P+Ti₅Si_3P/TiN+Ti₅Si₃/Si₃N₄.随着复合钎料中Ti元素含量的增加,钎缝中团聚的纳米Si₃N₄颗粒逐渐减少,母材侧的反应层厚度逐渐增加后趋于稳定.当Ti元素含量高于4%时,钎缝中形成了类似于颗粒增强金属基复合材料的界面组织;当Ti元素含量达到10%时,有少量Ti-Cu金属间化合物在钎缝中形成;钎焊接头的抗剪强度随着Ti元素含量的增加而呈现先增加后降低的变化趋势,当Ti元素含量为6%时接头的抗剪强度达到最高值,即75 MPa.     

Ni含量对304/Sn-8Sb-4Cu-xNi/304钎焊接头组织与剪切性能的影响

研究了Ni含量对Sn-8Sb-4Cu-xNi(x=0, 0.5, 1和2,质量分数)钎料熔点和微观组织的影响,用Sn-8Sb-4CuxNi钎料对304不锈钢进行钎焊连接,分析了接头的界面组织与剪切性能.结果表明,添加不同含量的Ni后,Sn-8Sb-4Cu-xNi均为近共晶钎料,其熔点约为245℃;Sn-8Sb-4Cu钎料组织由α相基体、Sb₂Sn₃+Cu₆Sn₅+Sn复合相和Cu₆(Sn,Sb)₅相组成.添加Ni元素后,钎料中块状Cu₆(Sn,Sb)₅转变为细小、均匀分布的(Cu,Ni)₆(Sn,Sb)₅.当Ni含量小于1%时,随Ni含量的增加,钎料中的复合相和(Cu,Ni)₆(Sn,Sb)₅相均增加;当Ni含量为2%时,钎料中的复合相和(Cu,Ni)₆(Sn,Sb)₅相均减少,但(...     

轧制复合铝/不锈钢界面金属间化合物的生长动力学

对轧制复合铝合金/不锈钢双层复合材料进行不同温度和时间的退火,借助Zeiss Ax10金相显微镜、Quanta-200型扫描电镜、EDAX能谱仪和D-max X射线衍射仪对复合界面结合区进行金相组织观察、元素成分线扫描分析、界面化合物EDS分析及XRD物相鉴定,研究复合界面上金属间化合物的生长行为。结果表明:复合界面金属间化合物(IMC)主要为Fe2Al5相,当退火温度达773 K时,Fe2Al5已在界面上生成;随退火时间的延长,Fe2Al5的增厚符合抛物线法则;界面金属间化合物Fe2Al5的生长激活能为162.3 kJ/mol,并获得其生长动力学模型,通过此模型可对化合物层厚度进行初步计算。     

Zn对钢-铝轧制界面组织与性能的影响

采用界面预置5%(质量分数,%)的Zn粉,冷轧复合成功制备出界面结合良好的钢-铝复合材料。通过XRD、SEM对复合材料界面形貌、界面物相及物相析出规律进行研究,利用自制滑轮剥离装置对界面剥离强度进行了测试。结果表明：钢-铝复合界面只生成Fe₂Al₅金属间化合物相,界面结合处预置Zn粉可延缓或减少Fe₂Al₅相生成,使生成Fe₂Al₅相的温度向高温推移。当热处理温度超过350 ℃后,界面预置Zn粉能显著提高钢-铝复合界面结合强度。     

镍/铜箔回流焊与激光钎焊界面显微组织与性能

基于镍箔“桥”替代铝铜直接焊接的背景下,利用回流焊、半导体激光钎焊对镍铜箔片进行异质连接.对比分析了接头形貌及界面显微组织的形成机制,并对其力学性能进行评价.结果表明,两种焊接接头成形良好,且无焊接缺陷产生;激光钎焊焊缝内由锡的固溶体和具有等轴晶形态的Cu-Sn金属间化合物组成,而回流焊焊缝则为锡的固溶体;两种焊接接头铜-锡、镍-锡界面均呈现不同形貌,且铜-锡界面层厚度大于镍-锡界面层.回流焊在铜-锡界面处显微组织呈扇贝状分布,其组成为铜固溶体→Cu₃Sn金属间化合物→Cu₆Sn₅金属间化合物;激光钎焊铜-锡界面处由多种Cu-Sn金属间化合物组成.在镍-锡界面处,回流焊呈现连续分布的(Cu, Ni)₆Sn₅金属间化合物,而激光钎焊则是由短棒状(Cu, Ni)₃Sn₄与条状(Cu, Ni)₆Sn₅组成,两种焊接接头最大剪切力可达320 N以上,远高于实际生产要求.基于此研究结果,可进一步明确激...     

铝/钢异种金属火焰钎焊接头组织和性能

通过扫描电镜、能谱分析和X射线衍射等方法研究了火焰钎焊时Zn-xAl钎料的润湿性能、铝/钢钎焊接头界面显微组织、金属间化合物层以及接头抗剪强度.结果表明,Zn-xAl钎料配合改性CsF-RbF-AlF₃钎剂,可以有效地去除母材表面氧化膜,从而提高钎焊接头力学性能.随着Al元素含量增加,钎料铺展性和填缝性随之提高,但是钎焊接头强度先升后降,Al元素含量为15%时,钎焊接头力学性能最佳.钎焊接头显微组织分析结果表明,金属间化合物主要为Fe₄Al₁₃相. Zn-xAl钎料中Al元素含量较低时,界面层由富锌相和Fe₄Al₁₃相组成.随着Al元素含量的增加,在Zn-25Al钎焊接头界面出现第二层金属间化合物Fe₂Al₅相.     

铝合金/不锈钢层状复合材料界面化合物生长行为

采用光学显微镜(OM)、X射线衍射仪(XRD)、扫描电镜(SEM)和能谱(EDS)研究了轧制复合铝合金/不锈钢(4A60/304、4A60/316、4A60/430、4A60/439、1050/304、1050/304)复合界面金属间化合物的生长行为。结果表明:4A60铝合金/不锈钢复合界面靠近铝侧存在Si元素富集区、4A60/316不锈钢复合界面靠近铝侧存在Ni元素富集区;当热处理温度为575℃时,4A60/316界面化合物生长常数最小为2.56×10~(-14)m~2/s,1050/304界面化合物生长激活能最低为95.94 kJ/mol;界面金属间化合物主要为Fe_2Al_5相,还可观察到FeAl_3、Fe_4Al_(13)相。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

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 Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

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.