共查询到20条相似文献,搜索用时 62 毫秒
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本文通过对镀镍法实验装置的改进和工艺参数的优化,较成功地实现了快速凝固铝合金粉末透射电镜样品的制备。 相似文献
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快速凝固耐热铝合金的现状和发展 总被引:7,自引:0,他引:7
采用快速凝固/粉末冶金技术可制备出含有大量过渡族元素的铝合金,这种铝合金具有优良的高温力学性能和热稳定性,并已发展成为一系列耐热铝合金。简要评述了耐热铝合金的研究现状、发展趋势及应用前景。 相似文献
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利用单辊急冷法制备了一种锌铝合金,通过XRD分析表明,合金相组成主要为过饱和相α’和富锌相η,以及微量的介稳定相ε-CuZn4。ESEM及TEM观察结果发现,快速凝固所得合金晶粒为等轴晶,并且极其细化,甚至达到纳米级别,其中Si元素以特殊圆薄片状单质存在,较高含量的Si元素未出现偏析,均匀分散在基体中。 相似文献
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喷射沉积快速凝固材料的研究及应用概况 总被引:10,自引:0,他引:10
喷射沉积是一种新型的快速凝固技术,近年来广泛应用于研究和开发多种高性能愉速凝固材料。简要介绍了喷射沉积技术的基本原理和特点,对其在快速凝固材料中的应用进行了综述。 相似文献
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The powder compact melting technique for aluminium foam production as practised today accepts a certain mismatch between foaming agent decomposition and matrix alloy melting temperatures. This mismatch is believed to influence the pore structure in an unfavourable way. Adjustment of TiH2 decomposition as well as liquidus and solidus temperatures of matrix alloys can be used to counteract it. Effects of TiH2 thermal treatments are investigated using thermal analysis. TiH2 variants gained via annealing treatments were used to produce aluminium foam precursor materials. As matrix for these specimens, aluminium based alloys with low liquidus and solidus temperatures were selected. Alloy systems considered include established combinations of aluminium with Cu, Mg, Si and Zn as well as special quaternary mixtures of these elements. First examinations presented include thermal analysis of alloys as well as studies on expansion vs. time and temperature relationships of precursor material based on new alloys and foaming agent variants. 相似文献
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XiujunHAN WenjingYAO BingboWEI 《材料科学技术学报》2003,19(6):553-556
Droplets of Co-37.6 wt pct Mo and Ni-47.7 wt pct Mo eutectic alloys were rapidly solidified during containerless processing in a 3 m drop tube. A kind of anomalous eutectic appears in these two eutectic alloys when undercooling is beyond 56 and 61 K, respectively. The two eutectic phases in anomalous eutectic were observed to grow in dendrite manner. The formation of anomalous eutectic is ascribed to the cooperative dendrite growth of the two independently nucleated eutectic phases. Current dendrite and eutectic growth theories are applied to describe the observed processes. 相似文献
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雾化沉积Al—Cu—Mg合金的显微组织 总被引:1,自引:0,他引:1
本文采用雾化沉积技术制备了大块A1—Cu—Mg合金快速凝固材料,对沉积态和经挤压及热处理后的材料组织进行了观察和分析。结果表明基体呈全部等轴晶并存在少量显微孔洞是沉积态组织的主要特征。过饱和固溶体、时效析出相以及变形和热处理过程中形成的弥散相构成了材料的主要强化相。 相似文献
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粉末冶金泡沫铝的研究进展 总被引:1,自引:0,他引:1
陈锋 《中国材料科技与设备》2006,3(1):18-19,31
泡沫铝是一种新型的超轻多功能材料。粉末冶金发泡法因能制备异型泡沫铝和泡沫铝芯三明治复合结构.可满足汽车、航天、航空和军工等领域的需求,已成为当前泡沫铝研究的热点方向.本文介绍了国内外粉末冶金泡沫铝方面的研究现状,指出了现存问题。并展望了今后的发展趋势。 相似文献
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快速凝固铝硅合金材料及其在汽车中的应用 总被引:2,自引:0,他引:2
本文介绍了快速凝固技术的特点及在高硅铝合金中的应用潜力,综述了快速凝固高硅铝合金的制取方法及研究现状,扼要总结了快速凝固高硅铝合金在汽车工业中的应用,最后提出这一研究领域中存在的问题及发展前景。 相似文献
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Rapidly solidified Al_(100-x)—Cu_x alloys(x = 5,10,1 5,25,35 wt%) were prepared and analyzed.High cooling rate increased the Cu solubility in 9.-AI matrix.The influence of the cooling rate on Cu solubility extension in Al was experimentally simulated.Thus the pouring was performed in metallic die and by melt spinning-low pressure(MSLP) technique.Melt processing by liquid quenching was performed using a self-designed melt spinning set-up which combined the cooling technology of a melt jet on the spinning disc with the principle of the mold feeding from low pressure casting technology.The thickness of the melt-spun ribbons was in the range of30—70 μm.The cooling rate provided by MS-LP was within 10~5—10~6 K/s after the device calibration.The obtained alloys were characterized from structural,thermal and mechanical point of view.Optical microscopy and scanning electron microscopy were employed for the microstructural characterization which was followed by X-ray analysis.The thermal properties were evaluated by dilatometric and differential scanning calorimetric measurements.Vickers microhardness measurements were performed in the study.In the case of the hypereutectic alloy with 35 wt%Cu obtained by MS-LP method,the microhardness value increased by 45%compared to the same alloy obtained by gravity casting method.This was due to the extended solubility of the alloying element in the α-AI solid solution. 相似文献
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Yeon-Wook Kim 《材料科学技术学报》2008,24(1):89-92
Mg-Al-Zn-M M (misch metal) alloy powders were manufactured by inert gas atomization and the characteristics of alloy powders were investigated.In spite of the low fluidity and easy oxidation of the magnesium melt,the spherical powder was made successfully with the improved three piece nozzle systems of gas atomization unit. It was found that most of the solidified powders with particles size of less than 50μm in diameter were single crystal and the solidification structure of rapidly solidified powders showed a typical dendritic morphology because of supercooling prior to nucleation.The spacing of secondary denrite arms was deceasing as the size of powders was decreasing.The rapidly solidified powders were consolidated by vacuum hot extrusion and the effects of misch metal addition to AZ91 on mechanical properties of extruded bars were also examined.During extrusion of the rapidly solidified powders,their dendritic structure was broken into fragments and remained as grains of about 3μm in size.The Mg-Al-Ce intermetallic compounds formed in the interdendritic regions of powders were finely broken,too.The tensile strength and ductility obtained in as-extruded Mg-9 wt pct Al-1 wt pct Zn-3 wt pct MM alloy wereσ-(T.S.) =383 MPa andε=10.6%,respectively.All of these improvements on mechanical properties were resulted from the refined microstructure and second-phase dispersions. 相似文献