Investigations of a nanostructured FeMnSi shape memory alloy produced via severe plastic deformation

Low-cost iron-based shape memory alloys (SMAs) show great potential for engineering applications. The developments of new processing techniques have recently enabled the production of nanocrystalline materials with improved properties. These developments have opened avenues for newer applications for SMAs. The influence of severe plastic deformation induced by the high-speed high-pressure torsion (HSHPT) process on the microstructural evolution of an Fe–Mn–Si–Cr alloy was investigated. Transmission electron microscopic analysis of the alloy revealed the existence of nanoscale grains with an abundance of stacking faults. The high density of dislocations characteristic of severe plastic deformation was not observed in this alloy. X-ray diffraction studies revealed the presence of ε-martensite with an HCP crystal structure and γ-phase with an FCC structure.     

Superior machinability of steel enhanced with BN and MnS particles

The strategy that replacing part of MnS with BN was proposed in order to decrease the sulfur content in sulfur based free-cutting steel. The effects of BN and MnS inclusions on the microstructure and machinability of the steel were systematically investigated. The results show that most of the BN and MnS inclusions exist individually in the steel and only a small amount of them are in a composite state forming either isolated particles or clusters of particles. In the case of multi-phased steel, the theoretical calculation predicts that the volume of large BN particles should be 0.7 times of the volume of large MnS particles. The machinability of this type of BN and MnS alloy steel over a wide range of cutting speeds ranging from a low speed appropriate for drilling to a high speed appropriate for turning is confirmed as being equal to or superior to that of an MnS reference steel, even though the sulfur content in the composite steel is only half that of the MnS steel. The aptitude for cutting effect of 240 ppm nitrogen and 115 ppm boron in the composite steel is demonstrated to be equivalent or even better than 1000 ppm sulfur in MnS free-cutting steel.     

Kinetics of discontinuous precipitation in Cu–20Ni–20Mn alloy

The morphology and growth kinetics of discontinuous precipitation (DP) in a Cu–20Ni–20Mn alloy were investigated in the temperature range of 523–673 K by optical microscopy, scanning electron microscopy, and transmission electron microscopy. A lamellar mixed structure consisting of alternating lamellae of a matrix and NiMn phase was observed in DP colonies. The volume fraction of regions formed by a DP reaction was determined by quantitative metallographic measurements. The kinetics of DP was evaluated on the basis of the Johnson–Mehl–Avrami–Kolmogorov equation, which resulted in a time exponent of approximately 1.5. We confirmed that the nucleation of the discontinuous precipitate was confined to grain edges or boundaries at an early stage of the reaction. The activation energy of DP process was determined to be approximately (72.7 ±7.2) kJ/mol based on the Arrhenius equation; this result suggests that DP is controlled by grain boundary diffusion. The hardness values exhibited good correlation with the volume fraction of DP; this correlation was attributed to the presence of the ordered NiMn phase.     

针形锂电池CR425的研制

采用Li—MnO2电池材料和工艺制造CR425锂电池．重点对正极活性物质的加工制备及电池组装工艺进行了试验和改进．通过XRD试验测试了热处理前后电解二氧化锰(EMD)的结构，对制备的电池在不同温度下进行恒电流和恒电阻放电，并对贮存1周、3个月和6个月电池的开路电压、短路电流、内阻及放电容量进行了测试．结果表明，电池性能完全满足CR425锂电池的技术要求，可作为夜间钓鱼时的发光浮标或商务通用笔夜间使用时的照明电源．     

双层钙钛矿Sr2FeMoO6，Ba2FeMoO6的电磁性质研究

分析了双层钙钛矿结构的锰氧化合物Sr2FeMoO6,Ba2FeMoO6物相结构和电磁学性质,对巨磁阻效应进行了探讨,揭示了Sr2FeMoO6样品为半导体导电性,Ba2FeMoO6样品为金属导电性.     

The controlling factors and distribution prediction of H2S formation in marine carbonate gas reservoir, China

Generally, there are some anhydrites in carbonate reservoir, as H2S is also familiar in carbonate oil and gas reservoirs. Nowadays, natural gas with high H2S concentration is usually considered as TSR origin, so there is close relationship between H2S and anhydrite. On the contrary, some carbonate rocks with anhydrite do not contain H2S. Recently, researches show that H2S is only a necessary condition of H2S formation. The reservoir porosity, sulfate ion content within formation water, reservoir temperature, oil/gas and water interface, hydrocarbon and some elements of reservoir rock have great controlling effects on the TSR occurrence. TSR deoxidizes hydrocarbon into the acidic gas such as H2S and CO2, and the H2S formation is controlled by TSR occurrence, so the relationship among reaction room, the contact chance of sulfate ion and hydrocarbon, the reservoir temperature has great influence on the TSR reaction. H2S has relatively active chemical quality, so it is still controlled by the content of heavy metal ion. Good conditions of TSR reaction and H2S preservation are the prerequisite of H2S distribu- tion prediction. This paper builds a predictive model based on the characteristic of natural gas reservoir with high H2S-bearing. In the porosity reservoir with anhydrite, the formation water is rich in sulfate and poor in heavy metal ion. Oil and gas fill and accumulate in the gas reservoir with good preservation conditions, and they suffered high temperature later, which indicates the profitable area of natural gas with high H2S-bearing.     

微乳液介质中5''-硝基水杨基荧光酮光度法测定微量锰

研究了在混合微乳液介质中 ,Mn(Ⅱ) - 5’ -硝基水杨基荧光酮 (5’ -NSF)的显色反应 ,在pH =9.5～ 10 .5的硼砂缓冲体系中 ,Mn(Ⅱ)与 5’ -NSF形成 1∶2的紫红色配合物 ,ε548=1.4 4× 10 5L·mol- 1 ·mL- 1 ,锰质量浓度在 0～ 0 .2 8mg·L- 1 范围内服从比尔定律。该方法用于岩石矿物及水中微量锰的测定 ,结果满意     

硫酸锰深度净化的研究

对用锰粉去除工业硫酸锰中杂质进行了探讨实验,结果表明:控制反应温度90℃,锰粉加入量1.9%,反应时间4 h,静置时间48 h后,工业二级硫酸锰可净化达到肥料级、饲料级硫酸锰产品标准。     

纳米CaCO3/丙烯酸树脂浆液的流变性

制备了纳米CaCO3/丙烯酸树脂浆液,当浆液(48 gZ-26、50g纳米CaCO3和83.3 g二甲苯)中分散剂添加量为3 g时,Casson屈服应力τc值最小,浆液的稳定性最好,与工艺条件优化时所得到的一致.纳米CaCO3/丙烯酸树脂浆液的流变性研究表明:该体系的流动特性符合Casson模型,其屈服应力τC较小,稳定性较好;浆液的黏度随剪切速率增加而显著下降,具有明显的剪切稀化特性,且随着纳米CaCO3含量增加,其剪切稀化趋势增强;在所考察的低剪切速率范围内,纳米CaCO3浆液具有明显的触变性,且纳米CaCO3含量越大触变性越大.图10,表7,参8.     

稀土在高锰钢中的应用

近年来，许多行业对高锰钢的需求量急剧增加，不少企业开发了这一产品。然而由于缺乏生产高锰钢铸件的实际经验和必要的理论知识而遇到了不少困难。鉴于此，本文就稀土改善高锰钢机械性能的机理、稀土在高锰钢铸件生产中的使用效果和生产高锰钢铸件的工艺等问题进行了详细的叙述。