真空热压烧结对高纯W-Si合金靶材性能影响

以高纯W-Si合金粉(>99.995%)为原料,采用真空热压烧结工艺制备高纯W-Si合金靶材。研究烧结温度、热压压力、保温时间等工艺条件对靶材密度、微观组织性能的影响。结果表明,烧结温度在1350~1380℃,热压压力25~30 MPa,保温时间1.5~2 h,可制备出相对密度99%以上、平均晶粒尺寸100μm以内的高性能W-Si合金靶材。     

低温真空扩散反应制备高性能TiAl合金粉

通过高能球磨均匀混合以及低温真空预烧工艺制备TiAl合金粉,原料为粒度43μmTi粉和9~12μmAl粉,研究不同温度下不同保温时间后Ti、Al混合粉的合金化程度。结果表明:高能球磨1h的Ti、Al混合粉在500℃保温2h,再在600℃保温3h能制得主要为TiAl相和少量Ti3Al相的合金粉,制备合金粉的平均粒径为20μm左右。     

FeNiCo预合金粉末的烧结特性及其在金刚石绳锯中的应用

通过多金属电解法制备FeNiCo预合金粉末,采用X射线衍射仪和扫描电子显微镜对预合金粉末及其烧结体进行形貌观察和物相分析,研究FeNiCo预合金粉不同温度烧结时烧结体的力学性能和磨损性能,并探讨其在金刚石绳锯中应用的可行性。结果表明:制备的FeNiCo预合金粉一定程度上实现合金化,粉末呈不规则状,粒度较细;FeNiCo预合金粉在800~840℃烧结时,烧结体硬度最大值为107.6 HRB,三点抗弯强度最大值为1638.3MPa,致密度最大值为96.2%,磨损质量损失为0.498~0.555g,烧结温度适应性较好。采用FeNiCo预合金粉为主要胎体成分制作金刚石绳锯锯切硬质石材时,切割效率为8.6 m~2/h,工具寿命为11.3 m~2/m,具有较好的综合使用性能。     

钛铝靶材的相结构对涂层的结构和性能的影响

研究了完全合金化和完全未合金化钛铝靶材的结构,并研究了采用磁控溅射法,通氮气与不通氮气条件下沉积涂层的成分、结构和性能,探讨了不同相结构钛铝靶材与其沉积涂层在成分、结构和性能之间的关系。     

预合金粉为黏结剂的TiC钢结硬质合金组织演变与强韧性研究

采用水雾化法制备了Fe-xMo(x=1.5、3.0、4.5、6.0)预合金粉,以这种粉末为黏结剂,采用粉末冶金工艺制备了TiC高锰钢钢结硬质合金。研究了Fe-Mo粉的Mo含量对烧结合金组织演变和强韧性的影响。对球磨粉的粒度检验表明,由于Mo元素的合金化作用,提高了黏结相粉末的硬度,因此,可以将混合粉末破碎得更加细小,提高了粉末的活性,有助于合金的烧结和致密化。合金的组织观察表明,采用Fe-Mo预合金粉为黏结剂可以显著细化和球化TiC硬质相,组织均匀。当合金中Mo的质量分数为1.15%(即Fe-3.0Mo为黏结剂)时,合金的组织最好,强度和韧性达到最大值,分别为2 296 MPa和12.67 J/cm~2。之后,合金的晶粒尺寸随着Mo含量的增加而增大,强韧性逐渐降低。因此,采用成分合适的Fe-Mo预合金粉为黏结剂可以显著提高合金的强韧性。     

喷雾干燥法制备钼合金微粉的研究

钼合金的制备过程广泛采用原料粉末混匀、坯料压制、烧结成型的粉末冶金方法，因此原料粉末混合的均匀程度、纯度、粉末粒径和形貌对钼合金制品的性能有重要影响。本文采用溶液喷雾干燥法制备前驱体粉末，再将前驱体粉末在氢气气氛下进行高温还原制备钼钨合金粉和钼钌镍复合粉，研究了喷雾干燥工艺参数（溶液浓度、进料速度、干燥温度等）和还原热处理工艺参数（还原气氛、温度、时间等）对钼合金微粉粒径、成分和形貌的影响，此外还分析了钼钨合金化和钼钌镍复合粉钎焊性能。结果表明，采用溶液喷雾干燥结合还原热处理工艺，可获得粒径0.5~3μm的球形钼钨固溶体合金粉和0.5~2μm的球形钼钌镍复合粉，且钼钌镍复合粉在钼板上钎焊时具有优异的润湿性。     

一种烧结铝合金的制备工艺

日本爱知县日立粉末治金公司（Hitachi Powdered Metals Co．,Ltd．）研发的一种烧结铝合金制备工艺在美国取得了专利,其专利号为US7166254B2。首先将快速凝固的Al-Si合金粉、Al粉和Cu粉或铜合金粉混匀,然后将混匀的粉末压制成形后进行烧结,如认为必要可进行热处理。Al粉的最大粒度≤100μm,而其平均粒度为45μm～75μm。     

高纯稀土钇靶材焊接技术

以高纯稀土钇材料、铜及6061Al合金材料为研究对象,研究了高纯稀土钇靶材的钎焊与扩散焊接性能。结果表明,稀土钇靶材对In焊料的浸润性差,需要对靶材进行金属化处理,提高靶材的焊接性能;研究不同钎焊焊接温度对稀土钇靶材焊接质量的影响,焊接温度越高靶材焊合率越高,与焊料的流动性提高有关;开展高纯稀土钇靶材与6061Al合金的扩散焊接技术研究,在焊接温度400℃,压力110 MPa,保温3 h的扩散焊接后,扩散区深度约为8μm,焊接界面实现冶金结合,焊接强度达到70 MPa,满足8~12英寸大尺寸靶材的高溅射功率要求。     

机械合金化合成Invar合金纳米晶粉体

采用商用FeNi30及FeNi50合金粉为原料通过机械合金化(MA)合成纳米晶Invar合金(FeNi36)粉体,研究了不同球磨时间的Invar合金粉体的物相组成、显微组织结构与形貌特征,探讨其合金化机制。结果表明:球磨初期(5~10 h),微锻造和冷焊过程使合金粉体呈扁平形复合层状结构,同时FeNi50中的Ni原子逐渐向FeNi30中扩散,发生成分均匀化;球磨40 h后,已形成了成分均匀的α'-Fe(Ni)固溶体,其平均晶粒尺寸约为12 nm。此时,机械合金化合成的Invar合金粉体呈球形,表面光滑,继续球磨,大颗粒粉体表面出现裂纹,并碎裂,导致粉体细化。     

纳米晶W粉和W-Ni-Fe预合金粉的制备

采用高能球磨法制备纳米晶W粉和W-Ni-Fe预合金粉，研究了不同的球磨材质包括硬质合金球(CCB)、钨球(TAB)和球磨转速、球料比及球磨时间等条件对球磨后粉末性能的影响。利用XRD，TEM和EDX分析球磨后粉末的晶粒尺寸、晶格畸变、形貌、结构变化及颗粒成分变化。结果表明：高能球磨法可制得10nm～80nm的W粉和W-Ni-Fe预合金粉，纳米级颗粒含量达80％以上。相同材质的钨球制得的纳米粉末综合性能较好。球磨过程中，粉末保持颗粒状结构，纳米级粉末颗粒形状最终趋于等轴化。     

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.