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小孔径泡沫铝的制备及压缩性能研究 总被引:2,自引:0,他引:2
在常规熔体发泡法基础上,采用添加0.5%Mg(质量分数,下同)以降低表面张力;发泡剂400 ℃,6 h+500℃,1 h氧化预处理以协调发泡剂分散均匀性与发泡过程关系;发泡搅拌60s以破碎初始气泡等措施,成功制备出了平均孔径1.3 mm、孔隙率70.5%、结构均匀的小孔径泡沫铝.泡沫铝及Al-9Si泡沫的压缩性能分析表明,随平均孔径减小,泡沫铝的屈服强度、致密化应变和能量吸收能力均明显提高,泡沫铝压缩性能随孔径减小而提高,与泡沫铝的孔结构因素及孔结构均匀性有关. 相似文献
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泡沫铝的制备方法及应用进展 总被引:12,自引:0,他引:12
概述了泡沫铝的各种制备方法研究进展。根据制备过程中铝的状态可以将制备方法分为三类:固相法、液相法、电沉积法。液态铝能够通过直接注入气体、加入发泡剂或生成过饱和固一气共晶体的方法制得泡沫铝,间接方法包括熔模铸造法和渗流铸造法。如果往铝粉末压块中加入发泡剂,通过加热使发泡剂分解同样能得到泡沫铝。类似的方法还包括粉浆烧结法、散粉烧结法等。最后描述了泡沫铝的结构和优良性能,并对泡沫铝在各领域的应用进行了概括和展望。 相似文献
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粉末冶金法可实现泡沫铝三明治结构面板/芯层的冶金结合,并在制备近终型泡沫铝异型件上优势突出。基于国内研究现状,本文完善了粉末冶金法制备工艺,并优化了泡孔结构。研究发现,芯层采用AlMg4Si8铝合金成分组成,钢质面板经边缘焊接密封处理后,当芯层粉末松装密度为1.12 g/cm3时,在1500 kN轧制压力、0.06 m/s轧制速度及55%轧制压下率下,对灌满芯层粉末的包覆面板进行450 °C热轧,获得了面板/芯层冶金结合、致密度高的发泡前驱体。另外,当发泡剂TiH2被低熔点Sn包覆预处理后,在发泡初期分解出的H2被液态Sn包裹,避免了在固态基体空隙间的扩散,减少了裂纹的产生,发泡前驱体在720 °C发泡300 s后可获得泡孔结构相对均匀、72.7%孔隙率的泡沫铝三明治结构。 相似文献
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采用加压渗流法制备不同特征参数的开孔泡沫铝,在50~1050MHz电磁波频率内研究了开孔泡沫铝的屏蔽特性,并探讨了泡沫铝的孔径和厚度对其电磁屏蔽性能的影响。结果表明:在50~1050MHz频率范围内,泡沫铝具有较好的电磁屏蔽性能,其屏蔽效能为25~75dB。在50~850MHz频率内,泡沫铝的孔径增大,其电磁屏蔽效能上升;但当频率在850~1050MHz之间时,孔径变化对泡沫铝屏蔽效能的影响可以忽略不计。在50~700MHz频率之间时,随着泡沫铝厚度的增加,其屏蔽效能增大,但当频率在700~1050MHz之间时,厚度对屏蔽效能的影响可以忽略。 相似文献
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氢化锆熔体发泡法制备小孔径泡沫铝 总被引:3,自引:0,他引:3
以ZrH_2为发泡剂,采用熔体发泡法制备铝基小孔径泡沫铝,分析其制备过程及影响孔结构的因素;优化实验室制备泡沫铝的工艺条件;借助图形分析方法表征泡沫铝的孔径分布,并与TiH_2制备的泡沫铝进行了对比;采用改进座滴装置研究铝合金与氢化物的润湿行为.结果表明:ZrH_2较适合制备小孔径泡沫铝;优化工艺条件为:Al 650 g,增粘剂Ca 的加入量2.5%,发泡剂ZrH_2的加入量1.0%,发泡温度680 ℃,搅拌时间1.5 min,保温时间2.5 min;制备的泡沫铝孔径均匀,平均孔径小于1.5 mm;ZrH_2在铝合金中的润湿特点是导致泡沫铝孔径较小的主要原因. 相似文献
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开孔泡沫铝的电磁屏蔽性能 总被引:5,自引:0,他引:5
采用加压渗流法制备不同特征参数的开孔泡沫铝,在50~1050MHz电磁波频率内研究了开孔泡沫铝的屏蔽特性,并探讨了泡沫铝的孔径和厚度对其电磁屏蔽性能的影响.结果表明:在50~1050MHz频率范围内,泡沫铝具有较好的电磁屏蔽性能,其屏蔽效能为25~75dB.在50~850MHz频率内,泡沫铝的孔径增大,其电磁屏蔽效能上升;但当频率在850~1050MHz之间时,孔径变化对泡沫铝屏蔽效能的影响可以忽略不计.在50~700MHz频率之间时,随着泡沫铝厚度的增加,其屏蔽效能增大,但当频率在700~1050MHz之间时,厚度对屏蔽效能的影响可以忽略. 相似文献
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发泡工艺参数对闭孔泡沫铝胞结构的影响 总被引:3,自引:0,他引:3
采用压缩空气法制备闭孔泡沫铝,研究空气流量、搅拌速度和发泡温度对胞结构的影响。结果表明泡沫铝的胞直径为4-11mm,密度为0.10-0.22g/cm3,孔隙率最高达96.3%;泡沫铝的胞直径随着空气流量和发泡温度的增大而增大,随搅拌速度的增大而减小,其中空气流量对胞直径的影响最显著;壁厚和结点尺寸随空气流量和搅拌速度的变化规律与胞直径相反;在相同的搅拌速度下,泡沫铝的密度随着胞直径的增大而减小且与胞直径存在对应关系,搅拌速度为600r/min时,关系式为ρ=0.0278 0.3602.e-0.132d。 相似文献
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The infiltration casting process for producing aluminum foam includes three steps: preparing precursor using NaCI particles, infiltrating molten aluminum and cleaning NaCI precursor. Defects occur during the preparation of aluminum foam with superfine open-cell structure, and influence the pore structure and performance of aluminum foam materials. The types of the defect and their forming mechanisms are analyzed in this paper. The defects include point defects and linear metal defects, and are caused by the defects in salt precursor and the insufficient infiltration of molten aluminum into precursor. With the choice of proper precursor preparation method and infiltration process parameters, the complete aluminum foam with superfine pores could be achieved. 相似文献
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通过激光焊接获得3种不同几何构型的双层金属点阵结构,再将闭孔泡沫铝切割后填充到其孔隙当中获得一种新型泡沫铝填充双层金属点阵结构。采用实验和有限元模拟的方法研究其准静态面外压缩载荷作用下的承载能力、吸能特性及机理、变形破坏模式等。结果表明,泡沫铝的填充能够有效改变空心点阵结构的后屈曲行为,提高点阵芯体单元的屈曲稳定性,具有明显的耦合增强效应,表现在承载及能量吸收效率的大幅提升,可达到对应空心结构的10倍以上。 相似文献
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《Acta Materialia》2008,56(5):1114-1125
An experimental investigation into the constant stress amplitude compression–compression fatigue behavior of closed-cell aluminum foam, both with and without lateral constraint, was conducted. Results show that while the early stages of strain accumulation due to fatigue loading are independent of constraint, the rapid strain accumulation stage behaviors are sensitive to the constraint. This was ascribed to the noticeable hardening with plastic deformation observed under constraint during quasi-static loading, which in turn reduces the effective maximum stress experienced by the foam specimen during fatigue loading. This was demonstrated through a simple empirical model that connects fatigue strain accumulation without constraint to that under constraint. Complementary X-ray tomography experiments suggest that the fatigue behavior of the foams is relatively less sensitive to morphological defects such as missing walls than the quasi-static mechanical properties such as plastic strength. Evaluation of the energy absorption behavior suggests that the damage that accumulates during fatigue does not affect the energy-absorbing ability of the foam adversely. 相似文献
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Effects of cell size on compressive properties of aluminum foam 总被引:3,自引:0,他引:3
1 Introduction Metal foams are a relatively new class of structural materials and offer a variety of applications in fields such as lightmass construction or crash energy management. In view of potential applications, the mechanical properties of foamed m… 相似文献
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Reimund Neugebauer Carsten Lies Jörg Hohlfeld Thomas Hipke 《Production Engineering》2007,1(3):271-278
Fast-moving machine tool assemblies should be light and rigid. Because of the lightweight construction and the dynamic loads
these assemblies are very often susceptible to vibrations. Aluminum foam sandwiches are laminates with an aluminum foam core
and compact cover sheets. The foam cores possess a high-energy absorption capacity. Machine tool assemblies made of aluminum
foam sandwiches offer very high flexural stiffness, together with comparatively light weight. Vibrations generated by machining
are damped very well due to the cellular structure of foam. The manufacturing process of foam sandwiches is in general well
understood, but there are still some open questions concerning the mechanisms of bonding and adhesion between cover sheets
and foam core. This paper tries to give answers to these questions. 相似文献
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ZHANG Heng-hua 《中国有色金属学会会刊》2008,18(4)
It is shown from experiment that the pure B contained salt exhibits little refining effect, while the pure Ti contained salt, especially the salt containing 5Ti/1B, shows obvious refining effect on the pure aluminum. Crystallographic study indicates that Al3Ti particle is a more suitable nucleation site for the aluminum matrix than (Ti, Al)B2 type particles (TiB2, AlB2 and (Ti,Al)B2), because there exist more coherent planes with aluminum matrix in the former. Thermodynamics estimation, X-ray diffraction (XRD) and SEM detection show that the refining mechanism of (Ti, B)-contained refiners is mainly contributed to the heterogeneous nuclei of fine Al3Ti particles dispersed in the melting, which comes from the reaction between the Ti and aluminum. (Al, Ti)B2 type particle shows little or no direct refining effect, but it will reduce the size of Al3Ti since the Al3Ti nucleates and grows along the (Al, Ti)B2 type particle interface. 相似文献
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Hiroki TANAKA Tadashi MINODA 《中国有色金属学会会刊》2014,24(7):2187-2195
研究了温轧下过渡元素对7475铝合金板材晶粒细化的影响。经350℃温轧、480℃固溶热处理后,用Zr代替Cr的7475铝合金具有稳定亚晶超细组织;平均亚晶直径接近3μm。结果表明,溶液中的Zr能稳定亚晶是因为温轧中析出了细小的Al3Zr粒子;另一方面,含Cr粒子化合物在温轧之前析出,并且在温轧过程中会变粗大。与传统冷轧7475铝合金板材相比,温轧细化亚晶板材具有独特的性能。固溶处理后的温轧板材,在厚度截面的亚晶组织具有高比例小于150的小角度晶界;温轧T6态合金板材的强度高于传统7475铝合金板材强度10%。温轧铝合金板材最显著的特点是,在与轧制方向呈45°时高Lankford(r)值为3.5,而其平均Lankford(r)值为2.2。高Lankford(r)值有利于组织演变为β-fiber织构,特别是强{011}(211)黄铜部分。同时,温轧板材也具有高的抗应力腐蚀开裂性能(SCC)。根据Kikuchi线和透射电镜分析,温轧T6板材形成的小角度晶界导致无沉淀析出带(PFZs)难以形成,这是导致抗应力腐蚀开裂性能提高的重要因素,其原因是晶界和晶内的电化学性能存在差异。 相似文献