半固态流变成形的技术关键与新进展

早期的半固态加工技术以触变成形为主,但流变成形越来越受到企业界的欢迎,正在成为半固态加工技术领域的新亮点.目前已经利用半固态流变成形生产了包括黑色金属在内的多种零件,显示了光明的应用前景.但是,半固态流变成形要达到规模应用,必须解决模具材料、半固态浆料的定量浇注及工艺过程的自动控制3大问题.     

陶瓷基复合材料伪半固态触变成形

半固态材料具有触变性和优良的组织结构,即成形零件质量好,力学性能与锻件的力学性能相近,成形零件的尺寸和精度能达到净近成形或净终成形,而传统陶瓷的制备主要根据粉末冶金方法通过成型和烧结工序完成.综合半固态金属加工技术、粉末冶金以及21世纪陶瓷成形发展的方向,提出了一种新型成形方法-伪半固态触变成形,从而为陶瓷复合材料以及高熔点材料在更多领域的应用起到了推进作用.     

高熔点合金半固态加工技术研究进展

半固态加工是一种综合传统铸造工艺和锻压工艺优点的近净成形技术,能有效地实现成形件控形与控性的统一。并且这种加工工艺能够实现短流程、低能耗和环保的要求,因此半固态加工工艺得到了迅速发展,在工业生产中实现了广泛的应用。近些年来,半固态加工技术在轻合金领域展开了大量的研究且成功应用于生产领域。高熔点合金由于其固液相温度较高,在进行半固态加工时仍然存在一些技术难点,因此高熔点合金的半固态加工研究相对较少。文章从高熔点合金半固态坯料(浆料)的制备,半固态成形工艺的研究和半固态成形模具的研究3个方面介绍了国内外高熔点合金半固态加工技术的研究进展。     

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     

半固态材料制备的研究现状和发展趋势

半固态加工的优越性完全依赖于半固态材料所需具备的特殊组织结构,即细小球状固态颗粒均匀悬浮于液态基体中而形成液固共存的半固态组织.对现有的半固态材料的制备工艺进行了总结,主要有机械搅拌法,电磁搅拌法,促进凝固过程形核,外加晶粒细化剂,SIMA工艺和雾化成型工艺.还结合半固态加工的工艺路径流变成形和触变成形,提出上述半固态材料制备方法的发展趋势.     

塑性加工技术的新进展(2000年美国国际机械工程大会暨展览会塑性加工研讨会综述)

介绍了2000年美国国际机械工程大会（IMECE）的概况。介绍了该会议与塑性加工相关的3个主题研讨会（金属成形进展、材料热加工和快速成形技术）的论文内容，讨论了塑性加工工艺控制与优化、板材加工、管材成形、材料数值模拟方法和计算模型方面的发展现状，介绍了液压胀管、半固态成形等热点研究工艺和一些新的塑性加工技术。     

塑性加工技术的新进展

介绍了 2 0 0 0年美国国际机械工程大会 (IMECE)的概况。介绍了该会议与塑性加工相关的 3个主题研讨会 (金属成形进展、材料热加工和快速成形技术 )的论文内容 ,讨论了塑性加工工艺控制与优化、板材加工、管材成形、材料数值模拟方法和计算模型方面的发展现状 ,介绍了液压胀管、半固态成形等热点研究工艺和一些新的塑性加工技术     

半固态材料成形应用

半固态加工是金属材料热加工的新兴技术，它与固态加工、液态加工同属金属加工领域：主要介绍了半固态金属浆料的制备、半固态加工的工艺方法、半固态加工的应用及未来发展趋势，以期推动其理论研究和工业发展。     

半固态金属加工技术研究现状与应用

半固态金属加工 (Semi SolidMetalProcessorSemi SolidMetalForming,简称SSM)是近年来金属加工技术研究的热点。总结了半固态金属成形的组织演变、流变行为以及坯料制备和成形工艺等方面理论与应用研究成果 ;对半固态成形技术的发展现状与趋势进行了分析和讨论 ;并从经济和市场需求角度分析半固态成形技术成本问题。介绍了半固态成形技术的应用范围 ,指出了半固态技术在汽车领域应用的广阔前景     

半固态连续触变挤压成形技术

半固态连续触变挤压成形技术是一种新的加工技术，将半固态技术，铸造和挤压技术融为一体的连续触变挤压技术，是半固态技术在材料制备领域的一个发展，文中主要针对复合材料，易偏析材料和脆性材料的制备。     

超音速火焰喷涂纳米结构涂层研究进展

超音速火焰(High Velocity Oxy -Fuel,简称HVOF)喷涂具有高速和相对较低的温度两个重要特征,能够获得比普通火焰喷涂或等离子喷涂(Plasma Spray,简称PS)结合强度更高的致密涂层.纳米材料具有独特的表面效应、体积效应及量子尺寸效应,其电学、力学、磁学、光学和热学等性能产生了惊人的变化.随着材料科学技术的深入发展, 在实际生产和生活中运用性能优良的纳米材料倍受人们关注,其中,采用热喷涂技术制备纳米结构涂层是构筑纳米结构材料的最具前途的方法之一.从目前国内外的情况来看,HVOF喷涂纳米结构涂层技术的研究取得了较大的进展.综合国内外文献,总结了HVOF喷涂制备纳米结构涂层的研究现状,着重阐述了热喷涂纳米涂层的基本过程和结合机理,指出了利用HVOF喷涂纳米结构涂层存在的问题,并对热喷涂纳米结构涂层的发展前景作了展望.     

Improvement of the matrix and the interface quality of a Cu/Al composite by the MARB process

The matrix accumulative roll bonding technology （MARB） can improve the matrix performance of metal composite and strengthen the bonding quality of the interface./n this research, for the fwst time, the technology of MARB was proposed. A sound Cu/AI bonding composite was obtained using the MARB process and the bonding characteristic of the interface was studied using scanning electricity microscope （SEM） and energy-dispersive spectroscopy （EDS）. The result indicated that accumulation cycles and diffusion annealing temperature were the most important factors for fabricating a Cu/AI composite material. The substrate aluminum was strengthened by MARB, and a high quality Cu/AI composite with sound interface was obtained as well.     

Gelcasting of titanium hydride to fabricate low-cost titanium

In this work, low-cost titanium was fabricated by gelcasting of titanium hydride powder. The effects of morphology and grain composition of powder raw material and solid loading on the rheological behavior of gelcasting slurry were studied. The degreasing, dehydriding and sintering behaviors of gelcasted green body were investigated by differential thermal analysis(DTA) and dilatometer.The results show that the solid loading of titanium hydride slurry reaches 50 vol%. Combination of dehydriding and sintering in one process accelerates the densification, and the relative sintered density of the final part achieves96.5 %. In order to test the ability of gelcasting process for fabricating structural materials, a resin handle produced by3 D printing technology was used as a model and a titanium handle was successfully fabricated. Higher solid loading and better sinterability of titanium hydride powder promote manufacture of bulk titanium with high relative density,complex shape and well-defined microstructure.     

Al-Si合金表面复合材料覆层处理

采用钎焊工艺,以Zn-Al 25作钎料,N2作保护气氛,在一系列工艺条件下,在Al-9Si基体上结合了Al-0.09w(Si) -0.15φ(SiCp)复合材料薄片。表面复合材料化Al-9Si合金零件的制成,为金属材料的表面处理提供了新途径,并对零件的性能作了研究。     

Clad metals by roll bonding for SOFC interconnects

High-temperature oxidation-resistant alloys are currently considered as a candidate material for construction of interconnects in intermediate-temperature solid oxide fuel cells. Among these alloys, however, different groups of alloys demonstrate different advantages and disadvantages, and few, if any, can completely satisfy the stringent requirements for the application. To integrate the advantages and avoid the disadvantages of different groups of alloys, cladding has been proposed as one approach in fabricating metallic layered interconnect structures. To examine the feasibility of this approach, the austenitic Ni-base alloy Haynes 230 and the ferritic stainless steel AL 453 were selected as examples and manufactured into a clad metal. Its suitability as an interconnect construction material was investigated. This paper provides a brief overview of the cladding approach and discusses the viability of this technology to fabricate the metallic layered-structure interconnects. This paper was presented at the ASM Materials Solutions Conference & Show held October 18–21, 2004 in Columbus, OH.     

SiC_p/2024铝合金复合材料粉末混合半固态挤压法制备

研究了SiCp/ 2 0 2 4铝合金复合材料的粉末混合 半固态挤压成形工艺及所制备材料的组织和界面特征。不同温度下半固态挤压的挤压力与位移曲线表明 ,半固态挤压过程的成形力低且稳定。SEM和TEM电镜观察结果表明 ,该工艺可以获得增强颗粒分布均匀、基体组织致密、界面结合良好且无界面反应的复合材料型材。分析了半固态挤压后复合材料的力学性能 ,结果表明 :与基体合金相比 ,复合材料的弹性模量、屈服强度、抗拉强度均有很大提高 ;与其它工艺生产的该复合材料相比 ,所制备的复合材料的塑性相对较高。     

Fabrication of metal matrix composites by metal injection molding—A review

Metal injection molding (MIM) is a near net-shape manufacturing technology that is capable of mass production of complex parts cost-effectively. The unique features of the process make it an attractive route for the fabrication of metal matrix composite materials. In this paper, the status of the research and development in fabricating metal matrix composites by MIM is reviewed, with a major focus on material systems, fabrication methods, resulting material properties and microstructures. Also, limitations and needs of the technique in composite fabrication are presented in the literature. The full potential of MIM process for fabricating metal matrix composites is yet to be explored.     

钨涂层及氧化镧合金面对等离子体材料研究

介绍了等离子体喷涂钨涂层和粉末冶金钨氧化镧合金面对等离子体材料的制备,并对其进行了性能分析,主要包括微观结构、杂质含量、气孔大小及气孔率分布、结合强度、热导率以及热负荷疲劳性能和承受能力。结果表明:真空等离子体喷涂钨涂层性能比大气喷涂钨涂层性能优越,是更为合适的钨涂层制备技术。真空喷涂钨涂层具有较低的气孔率、较高的热导率、较低的杂质含量和较优异的热负荷性能,能够承受10 MW/m²、100周次疲劳测试。氧化镧弥散掺杂相具有钉扎作用,能够抑制钨烧结过程中的长大,有效提高钨材料强度,改善热负荷性能,W-1%La₂O₃(质量分数)材料能够承受6MW/m²的热负荷。     

Predicting sintering deformation of ceramic film constrained by rigid substrate using anisotropic constitutive law

Sintering of ceramic films on a solid substrate is an important technology for fabricating a range of products, including solid oxide fuel cells, micro-electronic PZT films and protective coatings. There is clear evidence that the constrained sintering process is anisotropic in nature. This paper presents a study of the constrained sintering deformation using an anisotropic constitutive law. The state of the material is described using the sintering strains rather than the relative density. In the limiting case of free sintering, the constitutive law reduces to a conventional isotropic constitutive law. The anisotropic constitutive law is used to calculate sintering deformation of a constrained film bonded to a rigid substrate and the compressive stress required in a sinter-forging experiment to achieve zero lateral shrinkage. The results are compared with experimental data in the literature. It is shown that the anisotropic constitutive law can capture the behaviour of the materials observed in the sintering experiments.     

热喷涂制备TiB2涂层的研究进展

TiB2具有优良的性能和潜在的应用前景,采用粉末冶金制备致密块体材料的工艺复杂、成本高昂,限制了它的应用.涂层技术则是简化制备工艺、降低制造成本的有效手段.本文综述了热喷涂制备TiB2涂层的工艺特点以及TiB2物理化学特性对热喷涂制备工艺的影响,提出通过粉体复合技术改善TiB2粉体的物性,满足热喷涂工艺要求,从而获得高质量涂层的措施.