喷射成形硅钢板坯的工艺研究

利用自行研制的大型喷射成形中装置, 对Fe-4.5wt%硅钢板坯的喷射成形工艺进行了研究。还研究了雾化压力和沉积距离对其显微组织的影响。结果表明,在本试验条件下得出的最佳喷射成形工艺,可形成厚度均匀、晶粒细小并致密度良好的板坯,使随后的轧制成为可能。     

喷射成形钛铝合金的研究

喷射成形是一种快速凝固近终成形材料制坯技术，利用该技术制备的材料具有优异的性能，喷射成形技术产品在特定的领域正在逐步取代一些传统材料。简要阐述了喷射成形技术制备钛铝合金的研究发展现状，并指出制备喷射成形钛铝合金未来的方向。     

论喷射成形7055铝合金锻件的应用及相关标准制定情况

本文综述了喷射成形7055铝合金锻件的应用及相关标准制定情况。结合7055铝合金及喷射成形技术标准、喷射成形7055锻件的技术优势、喷射成形7055锻件的应用情况,论述了喷射成形7055铝合金锻件标准制定的意义和必要性。     

采用喷射沉积法制备耐热铝合金的工艺研究

利用自行研制的喷射沉积装置，作者研究了工艺因素对喷射成形制备Ａｌ－８Ｆｅ－２Ｖ－２Ｓｉ的坯料，并采用热轧等手段获取了组织性能优异的合金板材。     

基于凸轮驱动喷嘴分阶段变速扫描的锭坯喷射均匀沉积研究

喷射成形技术可以制备出高性能、高质量的工业锭坯,对工业的发展具有重要影响。雾化喷嘴系统是喷射成形装置的核心,喷嘴扫描运动方式对锭坯的均匀沉积有着重要的作用。本文以锭坯均匀沉积为目标,提出了基于凸轮驱动的参数可调的喷嘴扫描方式,建立了喷嘴分阶段变速扫描过程,确定了凸轮形状,对锭坯沉积轨迹进行了仿真并做了分析。最后用喷射成形实验对喷嘴分阶段变速扫描进行了验证,表明了其正确性。     

喷射成形技术的产业化现状及应用发展方向

综述了喷射成形技术在国内外的产业化两头主,并根据喷射成形技术的特点,探讨了国内喷射成形技术的几个重要应用发展方向。     

喷射成形过程中圆锭坯外形生长的数值模拟

通过多次试验后得出雾化喷嘴的雾化特性公式,在此基础上建立了一种模拟喷射成形过程中圆锭坯外形生长的数学模型.该数学模型考虑了喷射成形过程中各种工艺参数,如喷嘴的雾化参数、偏心距离、沉积盘的旋转速度和下拉速度等参数的影响.经过模拟计算,得到了锭坯生长的三维外形尺寸,与实际喷射成形制备的锭坯外形对比,二者吻合很好;采用该模型分析了不同时间下锭坯的轮廓形状、偏心距离以及下拉速度变化后的锭坯轮廓形状.综合分析得出,此数学模型可以预测在不同工艺参数下喷射成形锭坯的外形生长过程.     

喷射成形技术

喷射成形技术喷身成形是英国Ｓｗａｎｓｅａ大学的Ｓｉｎｇｅｒ教授在七十年代初最先提出来的一种金属成形新工艺，后来由英国Ｏｓｐｒｅｙ公司对该工艺及设备进行了大量的研究，发展成一种实用技术，并逐步实现了工业化．喷射成形的基本原理，是利用熔融的金属流雾化成金...     

非规则管坯喷射沉积成形工艺优化及试验验证

提出了基于往复式喷射成形工艺制备大璧厚非规则管坯的近终形成形工艺及其工艺参数优化方法,以实现坯件从CAD设计到喷射成形的快速制备过程。该工艺方法包括三个阶段:非规则管坯的三维CAD设计、分层处理和单层沉积厚度计算;基于沉积厚度与往复速度和质量流率的对应关系,计算满足各层沉积厚度所对应的控制参数;利用控制系统和执行机构对控制参数进行实时控制和调节,采用往复式多层喷射成形工艺制备满足设计轮廓的管坯。通过试验进行了验证,喷射成形制备的管坯形状和轮廓与CAD设计模型较好地一致,表明了该工艺方法的可行和正确性。     

喷射成形7A60合金的微观组织与力学性能研究

利用喷射成形技术制备了7A60合金. 借助扫描电镜（SEM）、透射电镜（TEM）、 X射线衍射（XRD）和拉伸试验等手段研究了该合金的微观组织和力学性能, 重点分析了喷射成形7A60合金沉积态中第二相的特点. 拉伸试验结果表明, 喷射成形7A60合金经T6处理后极限抗拉强度可达到733 MPa, 并且延伸率保持在9.5%左右.     

粉末冶金高氮不锈钢的研究现状

综述了粉末冶金高氮不锈钢的优点和所采取的主要工艺及国内外研究现状。系统总结了高氮不锈钢粉末的制备工艺和固化成形工艺。重点介绍了注射成形-烧结渗氮工艺,分析了部分产品的性能及应用前景,指出注射成形-烧结渗氮工艺是十分有潜力的制备高氮不锈钢的途径     

New trends in powder injection moulding

Powder injection moulding (PIM) is a rapidly growing technology for producing complex geometry, net shaped components from ceramics, metals, hard metals, and intermetallics. The shaping of ceramic powders using injection moulding has a highly creative aspect with regard to the complexity of the structural parts. This permits the most near-net shaping possible. Therefore, costly finishing of the sintered components can be reduced to a minimum or totally eliminated. This potential for ceramic injection moulding (CIM) has led in the recent past to intensified international research and development activities. A number of new binder systems have been developed, i.e., polyacetate based, PEG-polymer based, acrylic-polymer based, agarose-based, etc. The development in the area of new binder composition was in parallel assisted by a significant improvement in debinding processes. New debinding systems have been developed, i.e., computer assisted thermal debinding, extraction debinding, catalytic debinding, or even freeze drying or microwave assisted drying, which significantly shortened the debinding time from days to hours and lowered the emission of undesirable volatile organic by-products to a minimum. The formation of defects during the debinding process was also practically eliminated. Nitherlands Enegy Research Foundation ECN. Published in Poroshkovaya Metallurgiya, Nos. 3–4(406), pp. 16–23, March–April, 1999.     

高氮不锈钢粉末冶金制备技术的研究进展

高氮不锈钢作为一种重要新型工程材料,具有优异的力学性能和耐腐蚀性能,受到国内外广泛重视。介绍了粉末冶金制备高氮不锈钢的原理和特点;论述了高氮不锈钢粉末的制备与成形技术;指出了利用粉末冶金制备高氮不锈钢所具有的技术优势,其中注射成形——氮化烧结工艺更具发展潜力。     

高氮不锈钢粉末冶金制备技术的研究进展

高氮不锈钢作为一种重要新型工程材料,具有优异的力学性能和耐腐蚀性能,受到国内外广泛重视。介绍了粉末冶金制备高氮不锈钢的原理和特点;论述了高氮不锈钢粉末的制备与成形技术;指出了利用粉末冶金制备高氮不锈钢所具有的技术优势,其中注射成形——氮化烧结工艺更具发展潜力。     

陶瓷齿轮微注射成形工艺研究

研究了采用微注射成形技术(μPIM)制造含Y_2O_3稳定剂的ZrO_2微型齿轮.在含模温控制系统的注射机上注射成形,确定了注射参数,包括模具温度、注射压力和注射速度等.在室温下用C_2HCl_3溶液对注射样品脱脂,通过研究喂料和粘结剂的热分解性能,确定热脱和烧结工艺.结果显示,样品填充率高,表面光滑,有较高的致密度和表面硬度.     

Sintering densification for powder mixtures of varying distribution widths

A model for the sintering of bimodal powders is used to evaluate densification results for log-normal particle size distributions involving a constant median size on a weight basis. The model predicts a minimum in densification for distributions of intermediate width when the green density is held constant. This has been observed experimentally for sintered tungsten powders. As a consequence, wide particle size distributions are attractive for high packing and sintering densities, indicating possible new feedstock formulations for shaping technologies such as powder injection molding and slip casting.     

Ca2+/calmodulin-dependent kinase II mediates simultaneous enhancement of gap-junctional conductance and glutamatergic transmission

While chemical synapses are very plastic and modifiable by defined activity patterns, gap junctions, which mediate electrical transmission, have been classically perceived as passive intercellular channels. Excitatory transmission between auditory afferents and the goldfish Mauthner cell is mediated by coexisting gap junctions and glutamatergic synapses. Although an increased intracellular Ca2+ concentration is expected to reduce gap junctional conductance, both components of the synaptic response were instead enhanced by postsynaptic increases in Ca2+ concentration, produced by patterned synaptic activity or intradendritic Ca2+ injections. The synaptically induced potentiations were blocked by intradendritic injection of KN-93, a Ca2+/calmodulin-dependent kinase (CaM-K) inhibitor, or CaM-KIINtide, a potent and specific peptide inhibitor of CaM-KII, whereas the responses were potentiated by injection of an activated form of CaM-KII. The striking similarities of the mechanisms reported here with those proposed for long-term potentiation of mammalian glutamatergic synapses suggest that gap junctions are also similarly regulated and indicate a primary role for CaM-KII in shaping and regulating interneuronal communication, regardless of its modality.     

楔横轧窄台阶轧齐曲线的微分方程解法

为了解决目前轧齐理论应用于窄台阶轧齐曲线求解时精确性不足的问题,同时为了进一步了解轧齐成形本质,通过改进几何模型,分析并给出各影响因素之间关系函数,将轧齐曲线求解问题描述成为微分方程初值问题.通过软件编程应用数值方法进行求解,得到窄台阶轧齐曲线函数的离散值.使用有限元模拟计算及轧制试验的方法,将计算结果与文献作对比.通过对比分析模拟和实验结果中台阶面的尺寸,证明该解法不但是成立的,而且有利于成形更加精确的内侧较窄直角台阶.      

Shaping Stability and Temperature Field in Dual Frequency Electromagnetic Confinement and Shaping

Electromagneticconfinementandshaping(EMCS)isanewlydevelopedmaterialprocessing technique.TheEMCSprocesscombineselectromag neticcastingandelectromagneticlevitationwithad vantagesofbothtechniques.Theprincipleisthat themetalisheatedandmeltedbyinductiveheat,an…     

利用高氮化能力的熔剂精炼钢除氮

利用试验技术通过调整和精确控制１８７３Ｋ时的氧分压Ｐｏ２测定了Ａｌ２Ｏ３－ＣａＯ－ＴｉＯ２和ＣａＦ２－ＴｉＯ２熔剂中氮的溶解度和氮化能力。据试验发现，熔渣和铁水之间的氮分配比以及金属的脱氮度是Ｐｏ２的函数。文章研究了采用含ＴｉＯ２的熔剂从纯铁和铬合金钢中的除氮工艺，即首先把炉渣与金属粉末混合，然后在１８７３Ｋ坩埚中加热熔化，并将熔融金属从１０ｋｇ感应炉出钢至包中。系统中的氧分压可通过精炼剂中铝或钛含量进行调整。试验结果表明Ａｌ２Ｏ３－ＣａＯ－ＴｉＯ２渣可除去低合金钢中氮，脱氮度可超过６０％。文章讨论了生产过程中采用含ＣａＦ２－ＴｉＯ２熔剂的炉渣进行钢包处理有效去除高合金钢中氮的技术参数。