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针对熔模铸造制备的高孔隙率开孔泡沫铝(海绵铝),通过前驱体海绵孔棱增粗来提高海绵铝的相对密度,并研究孔棱尺寸对其压缩性能的影响。结果发现,采用水性聚氨酯树脂能有效增粗聚氨酯海绵孔棱,制备出孔棱厚度为0.472~0.918mm,相对密度为0.027~0.164的海绵铝。单向压缩试验结果表明,孔棱增粗显著提高了海绵铝的强度,当孔棱厚度为0.918mm时,其密实化平台应力最大,为2.831MPa,密实化吸能最大,达到1.492MJ/m3。这是由于孔棱厚度增加,相对密度提高,从而提高了海绵铝的能量吸收能力。 相似文献
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以青铜粉为原料、CaCl_2为造孔剂,采用粉末烧结溶解法制备开孔泡沫青铜。通过改变造孔剂体积分数和粒径成功制备出孔隙率为70%~90%,孔径1~3mm的泡沫青铜试样。研究了孔隙率和造孔剂的关系以及孔隙率、孔径对泡沫试样力学性能的影响,并对其孔结构,相组成和微观形貌进行观察和分析。结果表明:泡沫青铜试样的塑性屈服平台应力随孔隙率增加而减小,当孔隙率为77%~89%时,对应塑性屈服平台应力为12.6~2.6MPa。当应变量为50%时,孔隙率为77%~89%的泡沫青铜单位体积能量吸收值(W)范围为6.21~0.91MJ/m~3。试样的理想吸能效率(I)都接近0.82,说明泡沫青铜可以作为一种理想的吸能材料。 相似文献
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为了满足航空航天领域对高熔点开孔泡沫金属的迫切需求,针对现有开孔泡沫金属熔点低、强度和抗氧化性能差,以及孔隙率低、孔径结构分布不均匀等难题,以三维网状开孔泡沫Ni为基体,采用固体粉末包埋结合高温固相扩散工艺,制备出一种孔隙率达到95%三维网状开孔Ni-Cr-Fe泡沫合金。利用扫描电镜(SEM/EDS)对开孔Ni-Cr-Fe泡沫合金化前后的组织形貌和元素扩散进行分析,进一步了解扩散过程中Ni-Cr-Fe骨架形成与元素扩散之间的规律,并且对合金化后泡沫合金的微观形貌及结构进行表征。同时,研究了800℃和1000℃条件下开孔Ni-Cr-Fe泡沫合金的准静态压缩性能和能量吸收性能。结果表明:随着高温固相扩散时间的延长,网丝骨架中Cr、Fe、Ni元素浓度梯度明显平缓,(1200℃,48 h)均匀化热处理后,网丝骨架中Cr、Fe、Ni 3种元素发生了充分的互扩散,达到合金成分均匀化。并且,开孔Ni-Cr-Fe泡沫合金保持着初始泡沫Ni基体的三维网状及骨架中空结构。同时,高温压缩时开孔Ni-Cr-Fe泡沫合金具有典型韧性金属泡沫的变形特性,其压缩强度随着泡沫合金中Cr、Fe含量的增加而明显增大,而能量吸收性能表现出先增加后降低的趋势。 相似文献
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为避免传统方法制备大面积闭孔泡沫铝工艺过程的局限性,采用搅拌摩擦加工技术结合加热工艺制备闭孔泡沫铝复合材料。采用有限元软件对搅拌摩擦加工制备预制体过程的温度场进行了模拟仿真,研究了制备工艺参数对泡沫铝预制体质量的影响规律。利用光学金相显微镜对不同加工工艺参数及发泡时间条件下制备的泡沫铝孔隙率和形貌进行了分析。同时,对闭孔泡沫铝进行了准静态压缩性能试验,研究了不同孔隙率下泡沫铝的压缩性能。结果表明,与搅拌针移动速度相比,不同旋转速度对闭孔泡沫铝预制体的形貌影响更大。当搅拌针移动速度50 mm·min-1、旋转速度2000 r·min-1时,焊核区金属和夹层中的混合粉末发生了充分的塑性变形,粉末圈分布连续且均匀。模拟结果表明:搅拌摩擦加工时最高温度区域出现在搅拌针附近,呈“碗状”分布,此时温度达到最大值491℃,焊核区金属和夹层中的混合粉末发生充分塑性变形和流动,模拟结果与试验结果一致。经过680℃发泡后,泡沫铝最大孔隙率为69.3%,平均泡孔直径为Φ130μm,屈服应力为3.2 MPa,平台应力值为2.9 MPa。 相似文献
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The infiltration casting fabrication process based on spherical CaCl2 space-holders and the compressive behavior including the mechanical performance and energy absorption capacity of open-cell aluminum foams were investigated.Open-cell aluminum foams with different porosities in the range of 63.1%to 87.3%can be fabricated by adjusting compression ratios of CaCl2 preforms prepared by precision hot-pressing.The compression tests show that a strain-hardening phenomenon always occurs especially for open-cell aluminum foam with low porosity,resulting in the inclining stress-strain curve in the plateau region.The energy absorption capacity of open-cell aluminum foam decreases with increasing porosity when compared at the same strain.However,when compared at a given stress,each foam can absorb the maximal energy among the five foams in a special stress range.Additionally,open-cell aluminum foam possesses the maximum energy absorption efficiency at its optimum operating stress.At this stress condition,the foam can absorb the highest energy compared with other foams at the same stress point.The optimum operating stress and the corresponding maximal energy absorption decrease with increasing the porosity.The optimum operating stress for energy absorption can also be determined similarly when taking into consideration of the lightweight extent of foams. 相似文献
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胞状AlCu5Mn合金泡沫的压缩性能和能量吸收特性 总被引:2,自引:0,他引:2
用熔体发泡法制备孔隙率为51.5%~90.5%、孔结构均匀的胞状铝合金(AlCu5Mn),研究其孔结构、压缩性能、能量吸收能力、能量吸收效率和吸能性能.结果表明:胞状铝合金孔结构由高孔隙率(88.8%)时的大孔径、多边形孔向低孔隙率(62.5%)时的小孔径、球形孔孔结构过渡,其压缩应力(σ)-应变(ε)曲线具有线性变形阶段、屈服平台阶段和致密化阶段三个部分,由线性变形阶段进入屈服平台阶段所对应的ε_s值介于2%~9%之间;屈服强度σ_s~*随着孔隙率的增大而下降,在孔隙率相同的条件下,胞状铝合金的力学性能优于胞状铝和多孔铝合金,其比刚度高于钢;当应变为定值时,胞状铝合金单位体积和单位质量的压缩吸能能力(C和C_m)都随着孔隙率的升高而降低,但是孔隙率在73.5%~82.1%范围内时,其C_m与ε的关系几乎不随孔隙率的改变而改变;对于孔隙率为51.5%~90.5%的胞状铝合金,它们的吸能效率的峰值都大于80%.胞状铝合金的C-σ和C_m-σ关系可以表征其吸能性能,从而可以根据实际工况选择作为减振吸能材料的胞状铝合金的最佳孔结构. 相似文献
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本文采用粉末烧结-溶解法成功制备了孔隙率为63%~78%,孔径1.3~2.2mm的多孔CoCrNi中熵合金,借助SEM和XRD对试样的孔形貌和物相组成进行分析,并对试样进行轴向准静态压缩实验研究。结果表明:多孔CoCrNi中熵合金的弹性模量和屈服平台应力均随孔隙率、孔径的增大而减小;相对孔隙率而言,孔径对力学性能的影响程度较低;不同孔隙率的多孔CoCrNi中熵合金其致密应变下单位体积的能量吸收值为34.8~14.3MJ/m3,约为泡沫铝的3.8倍,且5种孔隙率的理想吸能效率(I)都接近0.8,说明该多孔CoCrNi中熵合金有潜力成为一种理想的吸能材料。 相似文献
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Sound absorption property of open-pore aluminum foams 总被引:1,自引:0,他引:1
The sound absorption property of aluminum foam was studied by testing its sound absorption coefficients using standing wave tube method. The open-pore aluminum foams were prepared by infiltration process, with pore size of 0.5 mm to 3.2 mm and porosity of 54.2% to 77%. The frequency of indicted sound wave was ranging from 125 Hz to 10 kHz. The results show that the average values of sound absorption coefficients are all over 0.4 and the aluminum foam has better sound absorption property, its coefficients is influenced by frequency and pore structure, and reaches the maximum at about 1 kHz, with increasing porosity and decreasing cell diameter the sound absorption coefficient values increase. 相似文献
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An open-cell aluminum foam filled with silicate rubber (AFFSR) was fabricated by infiltration of the liquid silicate rubber into the open-cell aluminum foam. The experiments were carried out to investigate the compressive behavior and energy absorption characteristics of the material. It is found that the stress--strain response of the AFFSR exhibits five regions including two plateau regimes, which is quite different from the stress--strain curves of many unfilled metallic foams that usually exhibit three distinct regions. The plastic deformation of the AFFSR is prolonged because of the filled silicate rubber, compared with the aluminum foam without such a filler. The AFFSR also exhibits a higher energy capacity than the aluminum foam without filler. Additionally, for the prolonged plateau region in the stress--strain curve, the energy absorption efficiency of the AFFSR maintains a high level (above 0.6) over a wide strain range from 3% to 60%. 相似文献
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In this study,Y-and Ce-modified Cr coatings applied by pack cementation method were prepared on the surface of open-cell nickel-based alloy foam.The morphologies and microstructures of Y-and Ce-modified Cr coatings with various Y and Ce contents were investigated in detail.Then,the effects of Y and Ce addition on the mechanical properties of open-cell nickel-based alloy foams were analyzed and compared.Simultaneously,the energy absorption capacity and energy absorption efficiency of the Y-and Ce-modified Cr coated alloy foams were discussed and compared at the room and high temperatures.The results show that Cr coatings containing minor amounts of rare earth element(Y and Ce) are well adhered to the nickel-based foam struts.Especially,the microstructure of the 2 wt% Ce-modified Cr coating is denser and uniform.In addition,the compressive strength and plateau stress of Y-and Ce-modified Cr coated alloy foams firstly increase and then decrease by increasing the Y and Ce contents at room and high temperatures.The energy absorption capacity of Y/Cr and Ce/Cr coated alloy foams increases linearly with the strains increasing.The Ce/Cr coated alloy foams can absorb more energy than Y/Cr coated alloy foams in the plateau and densification regions at room temperature.Compared to those at room temperature,the Y-and Ce-modified Cr coated alloy foams show higher energy absorption efficiency when deformation within 10%-30% at high temperature. 相似文献
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S. Gong Z. Li G.Y. XuN. Liu Y.Y. ZhaoS.Q. Liang 《Journal of Alloys and Compounds》2011,509(6):2924-2928
Cellular CuAlMn shape memory alloys with open-cell or closed-cell structure have been manufactured successfully by sintering-evaporation process. This process consisted of mixing CuAlMn and NaCl powders, hot pressing and final high-temperature sintering to evaporate the filler material of NaCl powders. NaCl was eliminated completely during vacuum sintering, and strong metallurgical bonding in the cell walls was achieved. The pores’ structural parameter (pore size, shape, and direction) and porosity (25-70%) have been controlled effectively. The compressing deformation behavior and phase transformation behavior of the cellular CuAlMn shape memory alloy has been investigated. It was found that the maximum stress of the cellular CuAlMn shape memory alloys increased with the decrease in porosity, and the energy absorption per unit volume approached the maximum value of 35.81 MJ/m3 (the compression direction parallel to the cross-section) and 25.71 MJ/m3 (the compression direction perpendicular to the cross-section) as the porosity of the alloys was 60% and the pore size was between 355 and 800 μm. 相似文献