水浸超声波探伤在黄金掺铱制品中的应用

采用水浸超声波探伤的方法对黄金掺铱制品进行快速检测,当扫查灵敏度增加到89d B时,可以观察到缺陷存在。用金相显微镜观察到样品中的铱,能谱扫描证实了铱的存在,为超声波探伤检测结果提供了佐证。     

利用大单晶生产铱制品

铂族难熔金属─铱是唯一一种能够在２０００℃温度的侵蚀性介质中使用的结构材料。生产铱制品时必须解决的一个主要问题是如何排除其晶界脆性。研究表明,利用直径５０ｍｍ～６０ｍｍ的大单晶作坯料,是解决铱晶界脆性最有效的方法。 叶卡捷琳堡有色金属加工厂开发了利用原生铱和不同等级合铱废料制取高纯铱的火法冶金工艺。铱深度提纯的最终阶段要采用电子束区域熔炼法培育大单晶。利用优质大单晶详细研究了铱和钉的物理机械性能,查明了这两种金属产生脆性的原因。 制定了设备的最佳工作规范,培育了规定完善程度的单晶。讨论了工业生产铱…     

黄金制品表层颜色变化的原因分析及处理方法

分析了黄金制品表面红斑与白斑的形成原因,在模拟条件下进行验证,并进行了消除红斑、白斑试验。结果表明,黄金制品表面的红斑可能为杂质氧化形成,可用热稀盐酸清洗去除;黄金制品表面的白斑可能为金汞齐,经450℃/30 min+910℃/10 min热处理可消除。2种处理方法对黄金制品原有表面光泽影响都很小,且都不影响原有成色以及质量。     

央行：个人携带200克以上黄金进出境须缴税

为了规范和促进黄金及黄金制品进出口业务发展，保护当事人的合法权益，央行按照相关法规起草发布了《黄金及黄金制品进出口管理办法（征求意见稿）》，向社会公开征求意见，截止日期为10月29日。征求意见稿规定，个人携带自用黄金及黄金制品进出境，重量超过200克的，应当主动向海关申报并凭中国人民银行及其分支机构出具的《中国人民银行个人携带黄金及黄金制品进出口准许证》办理交税、通关手续。     

我国黄金制品进出口管理范围扩大

为加强黄金及其制品的管理，近日中国人民银行联合海关总署发出公告，将黄金表壳、黄金表带纳入黄金及其制品进出口管理范围。根据公告，自2008年8月1日起，将黄金表壳（按重量计含金量在80％及以上）、黄金表带（按重量计含金量在80％及以上）纳入《黄金及其制品进出口管理商品目录》。     

黄金制品进出口管理办法（征求意见稿）

为进一步做好黄金制品进出口管理工作，规范黄金制品进出口行为，根据《中华人民共和国金银管理条例》，中国人民银行制定了《黄金制品进出口管理办法（征求意见稿）》，现向社会公开征求意见。     

黄金表壳、黄金表带纳入黄金及其制品进出口管理范围

为加强黄金及其制品的管理，根据《中华人民共和国金银管理条例》（国发[1983]95号文印发）有关规定，中国人民银行、海关总署日前发布公告，将黄金表壳、黄金表带纳入黄金及其制品进出口管理范围。     

铱片的显微组织与室温拉伸断裂机制研究

采用辉光放电质谱法(GDMS)、光学显微镜(OM)、扫描电镜(SEM)和力学试验机等测试手段,对不同加工状态的铱片杂质元素含量、金相组织、断口形貌和室温力学性能进行了研究。结果表明:加工状态对铱片的力学性能有重要影响,1 mm厚的热轧态铱片平均抗拉强度为213.6 MPa,延伸率为2.52%,主要为脆性沿晶断裂,部分为脆性穿晶解理断裂;而0.1 mm厚的冷加工态铱片平均抗拉强度为954.1 MPa,延伸率为0.55%,断裂模式主要为脆性穿晶断裂;两者在断裂之前均未发生明显的塑性变形,表现为脆性断裂模式。     

饰金新族——钛金

<正> 黄金或镀金制品,人见人爱。但黄金稀贵,价格很高,人们为了节约金子,又想得到制品表面具有金子那样黄灿灿的色泽,于是仿金镀层、仿金涂料和金属镀层相结合等技术应运而生,并且获得蓬勃的发展,为寻找黄金代用品开创了新路。 钛金是饰材的新族。钛金学名叫氮化钛,它是钛金属和氮气的化合物,为一种金黄色的粉末。氮化钛溅射镀可以得到金子一样色泽的仿金制品,镀层不是黄金,却胜似黄     

放射性同位素电池用铱合金包壳材料的研究进展

放射性同位素电池(RTG)对包壳材料的高温抗氧化性能有特别的要求,百瓦级以下的包壳材料可以使用Pt-30Rh合金,百瓦级以上的包壳材料需使用工作温度更高的铱合金。本文对铱合金包壳材料中掺杂钨、钍和铝等元素对金相组织结构、高温耐腐蚀性能和加工性能的影响,概述了高频感应熔炼、电子束熔炼和真空电弧熔炼等加工工艺的发展。     

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。     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

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.