铬铝多元共渗层组织和性能的研究

用固体铝热法对碳钢和中低合金工具钢进行铬铝多元共渗，对其渗层组织，相组成，硬度及耐蚀性，抗氧化性等进行研究。结果表明：铬铝多元共渗的外层组织均由含铬的碳化物，金属间化合物组成，具有较高的硬度和较优的耐蚀性及抗氧化性；铝量影响共渗的扩散层，硅量影响共渗层的致密性和脆性，它们都能使共渗层层厚显著增加；扩散层主要由铝铁化合物组成，硬度较低，它们也具有优良的耐蚀性和抗氧化性。因此，碳钢或中低合金钢及热作模     

铸铁固气法铬硅共渗过程的热力学分析

通过热力学分析和计算，表明固气法铬硅共渗过程初期以硅的渗入为主，硅的优先渗入为随后铬的扩散创造了条件，与单纯渗铬层相比，铸铁铬硅共渗层的连续性和致密性有所增强。     

铸铁铬硅共渗渗层组织特征及形成机制

采用固气法对铸铁铬硅共渗渗层的组织笔挺玫形成机制进行了分析和探讨。显微分析表明，渗层由α相和Ｃｒ７Ｃ３，Ｃｒ２３Ｃ６等碳化组成，其外表面富集的铬含量可达３０％以上，不含石墨，渗层下面为含大量珠光体的过渡区，靠近表面的渗层里，可观察到包围石墨的白亮环区。     

稀土硼铬共渗工艺及渗层性能的研究

研究了４５钢、Ｔ１０钢固体粉末法稀土硼铬共渗工艺及渗层的耐磨性、耐蚀性和高温抗氧化性能。发现ＲＥ－Ｂ－Ｃｒ共渗速度低于ＲＥ－Ｂ共渗，但稀土对硼铬共渗有明显的催渗作用，其最佳浓度为３％；ＲＥ－Ｂ－Ｃｒ共渗层具有较高的表面硬度和较小的硬度梯度，和渗硼层相比，耐磨性和耐蚀性分别提高３倍，抗７００℃氧化性提高１０倍左右。     

W18Cr4V低温盐浴硅铬共渗工艺及渗层性能研究

对W18Cr4V钢试样离子渗氮后在900℃以下进行盐浴硅铬共渗，分析了复合渗铬层的成分、组织、相结构和力学性能，并将硅铬共渗试样与单纯渗铬试样进行了耐磨性对比实验。结果表明，低温盐浴渗铬中添加硅能够增加铬的扩散速度，有效增加渗铬层厚度，提高渗铬层硬度、耐磨性，从而获得更佳的渗铬效果。     

铸铁铬硅共渗渗层组织特征及形成机制

采用固气法对铸铁铬硅共渗渗层的组织特征和形成机制进行了分析和探讨。显微分析表明，渗层由ａ相和Ｃｒ＿７Ｃ＿３、Ｃｒ＿２３Ｃ＿６等碳化物组成，其外表面富集的铬含量可达３０％以上，不含石墨。渗层下面为含大量珠光体的过渡区，靠近表面的渗层里，可观察到包围石墨的白亮环区。该环区很可能是因共渗过程中Ｃｒ、Ｓｉ原子在石墨周围局部聚集而形成的。保温时间延长，环内石墨消失，但仍保留环区特征。这种组织结构提高了铸铁的抗蚀能力及抗高温氧化能力。     

超高强度钢的Cr—Si原位CVD及耐蚀性研究

用单质铬粉、硅粉和ＮａＣｌ、ＮａＦ、ＡｌＦ３三元活化剂对３０ＣｒＭｎＳｉＮｉ２Ａ超高强度钢进行铬硅包渗，用正交试验法对工艺进行了优化，获得了含铬２９％、硅４％左右的铬硅渗层。渗层的表面为光亮的银白色，组织为柱状的α固溶体＋少量的Ｃｒ２３Ｃ６厚度为２００μｍ左右，表层显微硬度为３００ｋｇ／ｍｍ＾２，渗层在０．５ｍｏｌ／ＬＨ２ＳＯ４中浸泡腐蚀速度和在０．２５ｍｏｌ／ＬＨ２ＳＯ４中的电化学腐蚀速度均比未     

钒铬复合渗的研究

应用光学显微镜、显微硬度计、扫描电镜、电子探针和Ｘ射线衍射仪研究了Ｔ１０、４５、３Ｃｒ２Ｗ８Ｖ、９ＳｉＣｒ和ＧＣｒ１５钢在固体渗钒后，再进行盐浴渗铬的复合渗层的组织结构和性能。结果表明，钒铬复合渗层的厚度显著高于单渗钒层与钒铬共渗层。复合渗层具有高硬度、高耐磨性、高耐蚀性和抗高温氧化性等优良的综合性能，并可通过调整工艺改变复合渗层中渗钒层与渗铬层硬度的比例，来满足工件不同使用性能的要求。     

工具钢在氯系熔盐中的渗铬

研究了氯系熔盐渗铬剂的最佳成分与渗铬工艺,分析了各类工具钢在氯系熔盐中的渗铬层组织结构,测度子渗铬层厚度,硬度及耐磨性,考核了渗铬层的耐蚀性及氧化性。     

灰铸铁表面高铬铸铁铸渗层的组织与性能研究

采用铸渗工艺在灰铸铁表面制备高铬铸铁铸渗层,并研究了不同涂敷层厚度对灰铸铁表面铸渗层的铸渗质量、显微硬度及耐磨性能的影响。结果表明:涂敷层厚度为4 mm的试样,铸渗层深度最大,渗层组织分布均匀,铸渗层显微硬度在1200 HV以上,耐磨性是基体试样的2倍。     

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。     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.     

Microstructures and Mechanical Properties of a Newly Developed Austenitic Heat Resistant Steel

The effect of heat treatment on the microstructures and mechanical properties of a newly developed austenitic heat resistant steel(named as T8 alloy) for ultra-supercritical applications have been studied. Results show that the main phases in the alloy after solution treatment are γ and primary MX. Subsequent aging treatment causes the precipitation of M_(23)C_6 carbides along the grain boundaries and a small number of nanoscale MX inside the grains. In addition, with increasing the aging temperature and time, the morphology of M_(23)C_6 carbides changes from semi-continuous chain to continuous network.Compared with a commercial HR3C alloy, T8 alloy has comparable tensile strength, but higher stress rupture strength. The dominant cracking mechanism of the alloy during tensile test at room temperature is transgranular, while at high temperature, intergranular cracking becomes the main cracking mode, which may be caused by the precipitation of continuous M_(23)C_6 carbides along the grain boundaries. Typical intergranular cracking is the dominant cracking mode of the alloy at all stress rupture tests.     

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.     

The 15th Global Foundry Sourcing Conference 2014held in Qingdao China

Organized by Suppliers China Co., Ltd and co-organized by the National Technical Committee 54 on Foundry of Standardization Administration of China, the 15th Global Foundry Sourcing Conference 2014 （hereinafter referred to as FSC 2014） was successfully held on Sep. 23rd in Grand Regency Hotel, Qingdao. More than 500 delegates from home and abroad attended this conference, including over 130 purchasers from 20 countries and 380 domestic and foreign suppliers.     

Secondary Recrystallization Behaviors of Grain-Oriented 6.5 wt% Silicon Steel Sheets Produced by Rolling and Nitriding Processes

By rolling and nitriding processes, 0.23- to 0.3-mm-thick grain-oriented 6.5 wt% silicon steel sheets were produced. The core losses of grain-oriented 6.5 wt% silicon steel at frequencies ranging from 400 Hz to 20 k Hz were lower than that of the grain-oriented 3 wt% silicon steel with the same thickness by 16.6–35.8%. The secondary recrystallization behavior was investigated by scanning electron microscopy, energy-dispersive spectroscopy, and electron backscattered diffraction. The results show that the secondary recrystallization in high-silicon steel sheets develops more completely as the nitrogen content increases after nitriding, secondary recrystallized grain sizes become larger, and the sharpness of Goss texture increases. Because more {110}116 grains in the subsurface and the central layer of the sheets have a lot of 20°–45° high-energy boundaries in addition to Goss grains, {110}116 can be the main component through selective growth during secondary recrystallization when the inhibitor quantity is not enough and inhibitor intensity is weaker. The increases in nitrogen content can increase the inhibitor intensity and hinder abnormal growth of a mount of {110}116 grains and therefore enhance the sharpness of Goss texture.     

Laser Cladded TiCN Coatings on the Surface of Titanium

Laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs (OM). The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm / s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm - 2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2, and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80?滋m, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.     

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.     

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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