双峰颗粒级配熔模铸造用石英粉的研究

本文研究了石英粉颗粒级配及对涂料流变特性和工艺性的影响。双峰粒配石英粉涂料的流变参数τ0、n、k及流动阻力均较低,可增加涂料粉液比,从而改善铸件表面质量。生产试验铜铸件、铜铸件,在一定工艺条件下表面光洁度可达(?)6精选料配参数,粉液比高达1.6∶1时,ηc仅为18.4秒。     

钛合金熔模精铸ZrO_2(CaO)粉锆溶胶涂料层力学性能的研究

研究了ＺｒＯ２（ＣａＯ）粉锆溶胶涂层的常温抗弯强度和高温残留抗弯强度，并结合涂料层材料的热分析、受热线膨胀分析和断口的扫描电镜分析，运用多孔体强度理论，解释了工艺因素对涂料层强度的影响。     

球磨式涂料搅拌机

制备工艺性能良好的铸造涂料,是消失模铸造的一个十分重要的工艺环节。涂料工艺性能不仅取决于涂料的粉液比,密度和粘度,而且也取决于配制涂料的搅拌方式。不同的搅拌方式对于涂料的工艺性能有着直接的重要影响。作者在1997年为营口经济技术开发区东海铸造厂设计制造了一台球磨式涂料搅拌机,用于制备消失模铸造用的水基或醇基(铝矾土、石英粉、刚玉粉、锆砂粉等)涂料,取得了明显的技术效果。     

钛合金熔模铸造用新型氧化钇涂料的制备及其性能研究

制备了一种钛合金熔模铸造用新型氧化钇涂料,碳酸锆铵为粘结剂,氧化钇级配粉为耐火材料。该氧化钇涂料主要用作型壳的面层、次面层,研究了粉液比对涂料性能的影响。试验结果表明,粉液比为3.0 g/mL时,涂料性能最优,涂挂性最好。     

钛合金熔模精铸ZrO2（CaO）粉锆熔胶涂料层力学性能的研究

研究了ＺｒＯ２（Ｃａｏ）粉锆溶胶涂层的常温抗弯强度和高温残留抗弯强度，并结合涂料层材料的热分析、受热线膨胀分析和断口的扫描电镜分析，动用多孔体强度理论，解释了工艺因素对涂料层强度的影响．     

自硬转移涂料的研究

研究了适用于ＣＯ２水玻璃砂型的自硬转移涂料，提出了磷酸盐－镁砂粉做粘合剂的自转移涂料配方。应用自硬转移涂料时，模样表明应贴附硅橡胶面层，以减小涂料对模样的亲合力。生产验证表明，应用自硬转移涂料、ＣＯ２水玻璃砂型生产的铸件表面粗糙度达Ｒａ３．２～６．３μｍ，尺雨精度达ＣＴ６～８级。     

制备工艺对离心铸造涂料性能的影响

研究了三种最常见的涂料制备工艺对离心铸造涂料性能的影响,并分别对三种不同涂料的悬浮性、强度和流变性等进行测试、分析和比较。结果表明:3种制备工艺获得的涂料,在悬浮性能上,碾压法制备的涂料比搅拌法制备的高10%,比球磨法高20%;在强度上,碾压法刮下的涂料比搅拌法少0.025 6 g,比球磨法少0.343 5 g;在流变性上,碾压法制备涂料的流变曲线更加符合假塑形流体曲线。     

ZrO2粉双峰级配对钛合金熔模精铸涂料粘度的影响

研究了ＺｒＯ２（ＣａＯ）粉料双峰粒度级配中细粉颗粒自由充填粗粉间隙并获得较佳致密堆积效果的条件，研究了细粉相对含量对致密堆积系数、涂料相对粘度的影响。结果表明，涂料粉料粒度采用双峰级配后，细粉含量可在０～４３％之间进行调节，以获得适宜的涂料粘度，且双峰粒度涂料的固相含量，在相同粘度条件下，可比单峰粒度涂料高。     

脱硅提纯二氧化锆涂料的研究

利用等离子体法生产出优良理化性能的耐火填料脱硅提纯ＺｒＯ２．可配制出优质的铸钢涂料．实验测试和生产实验表明，纯ＺｒＯ２涂料是目前用于生产高合金钢铸件的最佳耐火涂料     

钛合金石墨型铸造用ZrO_2涂层性能研究

探索了粉液比对钛合金石墨型铸造用ZrO_2涂层常温性能及对铸件表面成形质量的影响规律。结果表明:粉液比对涂料的密度、粘度、悬浮性具有显著影响,粉液比为2.5∶1时涂料最适宜使用;相同粉液比条件下,厚壁铸件表面流痕少于薄壁铸件;相同壁厚条件下,高粉液比涂层铸件表面流痕少于低粉液比涂层铸件。     

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