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研究了不同变质剂P、S、RE以及P与S、P与RE对过共晶Al-Si合金的变质效果。结果表明:P与RE联合变质的变质效果最佳,既能细化初生硅,又能细化共晶硅。经P-RE联合变质的过共晶Al-Si合金,抗拉强度可达282MPa,耐磨性明显优于ZL108。 相似文献
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Cobalt is generally considered as the element that can promote the high-temperature mechanical properties of Al-Si alloys. In order to develop new hypereutectic Al-Si alloys that can be used at high temperature, the changes of microstructure of Al-20Si-2Cu-1Ni-0.6RE-xCo alloy with different contents of Co were studied in this paper. The results show that, under P-RE complex modification of the alloy melt, the content of Co varying from 0 to 1.5% had little influence on the refining effect of primary Si and modification effect of eutectic Si, but the amount of acicular RE-bearing Al-RE-Ni-Co-Si compounds gradually increased with the increase of Co content. In addition, Co could also modify the morphology of Fe-bearing phases, which solidified as particles instead of long needles. The addition of Co even has an adverse effect on the tensile strength of this RE-containing hypereutectic Al-Si alloy. 相似文献
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Tensile property of Al-Si closed-cell aluminum foam 总被引:3,自引:3,他引:3
1Introduction The unique properties of metallic foams make them useful in a number of potential application fields including damping,electromagnetic shielding,heat exchange,sound insulation,sound absorption,and energy absorption[1?4].The closed-cell alumi… 相似文献
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超高压凝固Al—Si合金的非平衡组织 总被引:19,自引:0,他引:19
研究了超高压(5.5GPa)条件下凝固的过共晶Al-Si合金的非平衡组织。结果表明:过共晶成分合金中出现大量初生α相。并有α-β+(α+β)共晶的共生组织,Si在α相中的固溶度和Al在β相中的固溶度都有极大增加。讨论了高压对凝固组织的影响。 相似文献
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Flow behavior of the Al-Si coated boron steel was investigated with Gleeble-3500, in comparison with the uncoated one. Effect of deformation conditions on the coating integrity was characterized by optical microscopy. Facture surfaces of the coated steels were inspected under SEM. Experimental results indicate that the ultimate tensile strength and ductility of the Al-Si coated boron steel are lower than those of the uncoated steel under test conditions. Extensive cracks occur in the coating after tensile tests; the width and density of cracks are sensitive to the deformation temperatures and strain rates. The bare substrate exposed between the separate coating segments is oxidized. Appearance of the oxide degrades the Al-Si coating adhesion. Remarkable difference between formability of the coating layer and the substrate is confirmed. The formability of the Al-Si coating could be optimized by controlling the phase transformation of the ductile Fe-rich intermetallic compounds within it during the austenization. 相似文献
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研究了Fe含量对高纯Al-Si合金力学性能的影响,并分析了Fe含量分别为<0.05%、0.1%、0.3%、0.5%时的金相组织和Fe含量<0.05%、0.5%、1.2%时的扫描断口。结果表明,对于高纯Al-Si合金,Fe含量小于0.5%时,随着Fe含量的增加,合金的抗拉强度和伸长率直线下降,当Fe含量增至0.5%~0.6%时,抗拉强度和伸长率基本降至最低值,而屈服强度略有升高。 相似文献
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介绍了AlSi12.5共晶合金和AlMn1.2(3A21)合金用双辊快速凝固法,制得0.28mm和0.45mm薄带,经退火后具有优良的冷轧性;AlSi12.5合金第一道压缩率30%冷轧时薄带边缘无裂缝,冷轧后强度较快凝态薄带提高11%,塑性也有提高。AlMn1.2合金第一道次压缩率50%,边缘无裂缝,冷轧后的强度较常规方法制得的3A21合金Y1硬化态提高40%。 相似文献
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The hypereutectic Al-Si alloy was fabricated by hot extrusion process after solidified under electromagnetic stirring,and the microstructure and mechanical properties of the alloy were studied.The results show that the ultimate tensile strength and elongation of the alloy reached 229.5 MPa and 4.6%,respectively with the extrusion ratio of 10,and 263.2 MPa and 5.4%,respectively with extrusion ratio of 20.This indicates that the mechanical properties of the alloy are obviously improved with the increase of extrusion ratio.After hot extruded,the primary Si,eutectic Si,Mg2Si,AlNi,Al7Cu4Ni and Al-Si-Mn-Fe-Cr-Mo phases are refined to different extent,and the efficiency of refinement is obvious more and more with the increase of extrusion ratio.After T6 heat treatment,the sharp corners of these phases become passivated and roundish,and the mechanical properties are improved.The ultimate tensile strength of the extruded alloy after T6 heat treatment reaches 335.3 MPa with extrusion ratio of 10 and 353.6 MPa with extrusion ratio of 20. 相似文献
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脉冲电场对KS282合金凝固组织的影响 总被引:1,自引:1,他引:1
以KS282合金凝固组织中的初生硅相作为对象,研究了脉冲电场孕育处理对KS282合金初生相形态的影响,分析了扫描电子显微镜(SEM)下组织形态的变化、断口金相,以及DSC曲线中凝固点位置的改变。结果发现,电脉冲孕育处理对多元高硅铝合金有变质作用,增加了合金凝固过程的热力学过冷度,提高了初生硅相形核率。 相似文献
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The Al2O3-SiO2(sf) (volume fraction, 20%)/Al-12.6Si metal matrix composites(MMCs) with or without rare earth Pr addition were fabricated by infiltration squeeze method. Effect of Pr addition on microstructures and fractographs of Al-Si MMCs was investigated by SEM and TEM. Tensile properties at room temperature and 200 °C were tested. It is shown that the addition of Pr is favorable to produce uniform microstructures and modify the eutectic Si crystal effectively. Compounds/intermetallics with high content of Pr are formed at the interface between short fiber and matrix. Yield strength(σ0.2), ultimate tensile strength(σb) and fracture elongation of Al-Si MMCs are improved by adding suitable amount of Pr. Compared with those values of Al-Si based MMC at 200 °C, σ0.2 and σb of MMC with 0.29% Pr are increased by 33% and 55%, respectively. The tensile fracture surface of Al-Si MMCs with Pr addition presents ductile fracture features. 相似文献
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Effect of electric pulse modiifcation on mircostructure and properties of Ni-rich Al-Si piston alloy
《中国铸造》2016,(2):139-142
In order to improve the properties of Ni-rich (2.5wt.%) Al-Si piston aloy, electric pulse modiifcation was applied in fabricating the Ni-rich Al-Si piston aloy in this study. The effect of electric pulse modiifcation on the mechanical properties of the Ni-rich Al-Si piston aloy was studied using optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), microhardness measurement and tensile strength testing. The results showed that the microstructures of Ni-rich Al-Si piston aloy treated by electric pulse modiifcation were reifned, the solid solubility of Cu, Ni, Si, etc. inα-Al matrix was improved, and furthermore, the microhardness and high-temperature tensile strength were increased by 9.41% and 17.5%, respectively. The distribution of second phases was also more uniform compared with that of a non-modiifed sample. 相似文献
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The microstructure of hypoeutectic Al-9.21wt.%Si alloy solidified under 5.5 GPa was studied. The results show that the solidification microstructure is refined. The primary a phase is the extended solid solution.The solid solubility of Si in a phase is up to 8.26wt.%. The growth mode of the a phase is cellular, and this cellular growth mechanism is interpreted in terms of the decrease of the diffusivity and the extended solid solution under high pressure. By calculation, it can be known that the the diffusivity of solute in the liquid under normal pressure is as high as two hundred times that under high pressure. The microhardness of the hypoeutectic Al-Si alloy solidified under high pressure is higher than that of solidified under normal pressure. After annealing, Si precipitates from the solid solution, the microhardness of the alloy decrease, but, still higher than that of solidified under normal pressure. 相似文献
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ZL114A合金是我国自主研发的铸造亚共晶Al-Si合金,变质共晶Si是提高其室温综合拉伸性能的重要方法之一。利用室温拉伸试验、扫描电镜观察研究了Sb元素对金属型铸造条件下ZL114A合金铸态和热处理态组织以及性能的影响。结果表明,对于铸态的ZL114A合金,Sb的加入将共晶Si由板片状变质为纤维状或颗粒状;经过热处理的ZL114A合金,Sb的加入使共晶Si的长径比变小,球化程度更高。在金属型铸造条件下,Sb元素能够提高ZL114A合金铸态和热处理态的室温综合拉伸性能,热处理后添加Sb的合金的抗拉强度和伸长率远远高于我国航空标准所要求达到的值。综合考虑ZL114A合金铸态和热处理态的共晶Si相形貌以及室温拉伸性能,Sb元素的最佳含量(质量分数)为0.09%。 相似文献
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1 INTRODUCTIONPractically ,mechanicalstirringandelectromag neticstirring (EMS)arewidelyusedtogenerateforcedflowinsolidificationandcastingofmetalsandalloys,resultingin greatchangesofthesolidifiedstructures,segregationsand propertiesofthecast ings .Muchattentionhasbeenpaidtosolidificationofdendriticalloyssuperposedwithforcedflow ,andmanypreviousworkshavebeenfocusedontheeffectsoffluidflowonthestructuraltransitions,suchascolumnar equiaxedtransitions(CET)ormacro segre gationinthealloys[13] .… 相似文献
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1 INTRODUCTIONDiscontinuously(particle,whiskerandshortfiber)reinforcedaluminumalloycompositeshavebecomeanattractivestructuralmaterialformanyindustrialfieldsowingtoitsexcellentproperties(e.g.highspecificstrength,highspecificstiffnessandgoodwearresistance)… 相似文献
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U?ur B?yük 《Metals and Materials International》2012,18(6):933-938
Al-11.1wt%Si-4.2wt%Ni alloy was directionally solidified upward under different conditions, with different growth rates (V=4.60?C243.33 ??m/s) at a constant temperature gradient (G=5.82 K/mm) and with different temperature gradients (G=2.11?C5.82 K/mm) at a constant growth rate (V=11.63 ??m/s) by using a Bridgman type directional solidification furnace. The microstructure of directionally solidified Al-11.1wt%Si?C4.2wt%Ni alloy was observed to be irregular plates of Al3Ni and Si within an ??-Al matrix from quenched samples. The microhardness, tensile strength and electrical resistivity of the alloy were measured from directionally solidified samples. The dependency of the microhardness, tensile strength and electrical resistivity for directionally solidified Al-Si-Ni eutectic alloy on the solidification parameters were investigated and the relationships between them were experimentally obtained by using regression analysis. Additionally, the variation of electrical resistivity with temperature in the range of 300?C825 K for the Al-Si-Ni eutectic cast alloy was also measured using a standard d.c. four-point probe technique. The enthalpy of fusion and specific heat for the same alloy were determined by a differential scanning calorimeter from the heating curve during the transformation from eutectic solid to eutectic liquid. The results obtained in the present work were compared with previous similar experimental results. 相似文献
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通过改变Si的含量,对发动机缸盖用铸造铝硅合金力学性能进行了研究。结果表明,随着Si含量的提高,铸造Al-Si合金的常温、250℃高温抗拉强度先升高,再降低,在共晶点附近达到最大值,其中高温抗拉强度的提高幅度明显。而合金的硬度先是缓慢上升,过了共晶区域后则急剧上升。与国外的常用缸盖材料的力学性能进行对比后发现,所研究的发动机缸盖用铸造铝硅合金具有优良的综合力学性能。 相似文献