第八届合金与复合材料半固态加工国际会议在塞浦路斯举行

第八届合金与复合材料半固态加工国际会议于2004年9月20日至24日在塞浦路斯举行．本次会议在铝合金、镁合金及复合材料、铜合金、铅锡合金以及高熔点合金的半固态流变成形和触变成形方面进行了交流．并对半固态加工技术在工业领域的应用、半固态坯料(浆料)的制备新工艺、半固态坯料(装料）的微观组织与性能以及半固态设备的研制等问题进行了探讨．我国学者罗守靖、康永林、谢水生、杨湘杰、杜之明、姜巨福、李涛、李兴刚、田展峰组团出席了本次会议。     

轻金属前沿制造技术的研究进展

铝镁等轻合金作为绿色工程结构材料是实现汽车、轨道交通和航空航天轻量化的重要手段,而材料加工技术的创新是轻量化关键所在.重点分析了轻合金的半固态成形、高真空压铸、等温挤压、等温锻造等几种国内外先进成形技术的研究现状、工艺特点、存在问题、关键技术及研究前沿,并指出了以计算机仿真为代表的有限元数值模拟技术在改善轻合金的成形性能方面日益成为轻量化的研究重点和发展趋势.     

铝合金半固态加工技术的应用研究

重点介绍了近年来在铝合金半固态坯料制备方面的研究进展以及在半固态触变成形技术工业应用方面的研究开发工作,如复合电磁搅拌制备半固态浆料、多流电磁搅拌半固态连铸技术、铝合金半固态触变压铸成形、铝合金半固态触变模锻成形等,并就其可能的应用领域及发展状况如难铸造合金的铸造成形、变形合金的直接铸造成形、活塞合金的加工成形、变形铝合金的塑性加工进行了讨论。     

铝合金的半固态成形

半固态加工是金属材料成形领域中的一种新工艺。分析了铝合金半固态成形技术的现状及发展趋向。     

半固态成形轻合金的发展状况

半固态成形技术以其高效、节能、近净形生产以及成形件性能高等诸多优点，已成为21世纪最具发展前景的金属成形工艺之一，但是半固态成形轻合金应用品种的局限性，制约了半固态成形技术的发展。文中介绍了国内外半固态成形轻合金的研究、应用状况以及新型半固态轻合金的设计开发，并分析了半固态成形轻合金的发展前景。     

铝合金半固态成形技术

介绍了铝合金半固态成形工艺；对半固态合金料的制备、成形方法及其优越性进行了讨论。简述铝合金半固态成形技术的研究和应用现状。     

低熔点合金半固态流变成形工艺开发应用研究

利用金属浆料通过旋转的内外筒之间的缝隙形成剧烈剪切应力场作用的原理,自行开发了一种新型的低熔点轻质合金半固态浆料制备与直接流变成形装置.通过以Sn-15Pb合金、Mg-30Zn合金和AZ91镁合金为原料,进行半固态浆料制备并直接近终成形的试验,得到晶粒细小、组织均匀的半固态加工产品,说明新开发的流变成形装置的实用性和可行性.本装置的开发对半固态加工成形技术的工业应用提供了一个新思路.     

金属半固态加工技术

半固态加工技术是一种新的材料成形技术。本文综述了半固态金属成形的成形工艺、坯料制备工艺、微观组织、国内外研究应用情况 ,展望了半固态加工技术的前景 ,并提出了应对措施     

半固态金属成形件的组织和性能研究进展

简要论述了半固态成形工艺参数对合金凝固组织的影响规律,指出合理控制各工艺参数是获取高性能半固态成形件的关键;重点综述了半固态金属成形件性能研究领域的最新进展;最后针对目前性能研究中存在的问题,展望了今后的研究方向。     

半固态成形技术最新进展——第11届合金与复合材料半固态成形国际会议技术报告综述

两年一次的合金与复合材料半固态成形国际会议是半固态成形领域内水平最高的学术会议.第11届合金与复合材料半固态成形国际会议于2010年9月16-18日在北京召开.会议发表的技术报告,内容涉及材料开发及合金设计,组织及性能,流变行为、模型及数值模拟,工艺开发,工业应用等.     

胫骨生物陶瓷复合材料的微结构增韧机理

扫描电镜观察显示胫骨是一种由羟基磷灰石和胶原蛋白组成的自然生物陶瓷复合材料.羟基磷灰石具有层状的微结构并且平行于骨的表面排列.观察也显示这些羟基磷灰石层又是由许多羟基磷灰石片所组成,这些羟基磷灰石片具有长而薄的形状,也以平行的方式整齐排列.基于在胫骨中观察到的羟基磷灰石片的微结构特征,通过微结构模型分析及实验,研究了羟基磷灰石片平行排列微结构的最大拔出能.结果表明,羟基磷灰石片长而薄的形状以及平行排列方式增加了其最大拔出能,进而提高了骨的断裂韧性.     

Prospects of the Use of Synergetic Approach to Solution of Problems of the Science of Nanomaterials

A synergetic approach to solution of problems of self-controlled synthesis of nanostructures and creation of self-organizing nanotechnologies is considered in connection with the superproblem of creation of materials with functional properties resembling those of biosystems. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 55 – 61, July, 2005.     

Kinetics of the oxidation of metals — Influence of self-diffusion of metal

The importance of the self-diffusion of a metal during its oxidation by a gas is treated for the cases of nonstoichiometric oxides having either interstitial cation or cation vacancies. We have established a general relationship for the reaction rate when a mixed diffusion process occurs. From this relationship, we have shown that the pressure dependence can be different, according to whether the rate-determining process is the self-diffusion through the metal or through the product.     

Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

Conclusions To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A necklace-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (+)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment.To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 25–29, December, 1991.     

Ab-initio calculation of enthalpies of formation of intermetallic compounds and enthalpies of mixing of solid solutions

A large number of ab-initio calculations of energies of formation of intermetallic compounds have been performed in the last 15 years. The currently used methods are listed. The paper presents a review of the aluminium based compounds which have been studied. Comparisons of calculated and experimental enthalpies of formation are provided for aluminim-3d and-4d transition metal alloys at equiatomic composition. The modelling of the enthalpies of mixing of solid solutions based on a given lattice is described.     

试论洋务派教师聘任的思想

洋务派在洋务学堂的办学活动中,为了解决西学专业学科的教学困难,采用了聘请外籍教师的应急措施.他们以真才实学,合同制管理作为主导思想,并认为这种解决师资的途径只是权宜之计,并非久远.从客观上看,洋务派的教师聘任思想有深刻的历史影响.