多孔铜合金高温压缩蠕变行为的数值模拟

采用RDL05电子蠕变疲劳试验机,在不同温度(550,600,650,700℃)以及不同应变速率(10-4,10-3,10-2/s)条件下对多孔铜合金进行高温压缩实验,获得多孔铜合金真应力-应变曲线,计算并得到相应温度下的蠕变本构方程.采用ANSYS软件对多孔铜合金进行高温压缩蠕变模拟,研究了孔径、载荷、孔形等因素对多孔铜合金蠕变性能影响.研究结果表明,孔径越大,温度、载荷越高,多孔铜合金蠕变变形越大,蠕变速率更快,蠕变性能越不稳定;在蠕变过程中,内棱孔壁处容易引起应力集中;孔隙形貌对多孔铜合金结构影响很大,随着孔形边数的增加,多孔铜合金结构越不稳定;在相同载荷下,三角形孔压缩量最小,圆形孔压缩量最大.

多孔铜铬合金的制备及催化氧化性能

以无水K2CO3作为造孔剂,采用粉末填充烧结法制备了多孔铜铬合金。利用X射线衍射仪(XRD)、扫描电镜(SEM)和电化学等手段分析了Cr含量与烧结气氛对其孔隙率及显微形貌的影响,并研究了Cr含量对甲酸催化氧化性能的影响。结果表明:使用惰性气体作为保护气氛烧结的多孔铜合金的孔隙率较高,可达到35%;Cr粉的添加显著提高了甲酸电催化氧化的活性,与多孔纯铜相比,添加0.6%Cr粉的多孔铜合金的电流密度提高了5倍。

空间占位法制备多孔Ti-5Cu合金及性能的研究

以钛粉和铜粉为原料,碳酸氢铵为占位剂,应用粉末冶金的方法制备出多孔Ti-5Cu合金,并对其微观结构和力学性能进行表征。结果表明:碳酸氢铵作为占位剂时,其添加量对制备出的多孔Ti-5Cu合金的相组成没有明显影响,但对其孔结构和力学性能有显著影响。当加入的碳酸氢铵量增加时,多孔Ti-5Cu合金的孔隙率随之增加,大孔结构变得相互连通;其弹性模量和抗压强度均降低,可通过调整碳酸氢铵的添加量调整其与自然骨近似匹配,有潜力用作多孔抗菌硬组织植入体。

凝胶注模成形制备铜锡多孔材料的研究

采用非水基凝胶注模工艺,对铜锡复合粉体进行了成形与烧结的研究。非水基凝胶注模的单体为甲基丙烯酸-2-羟基乙酯,溶剂为1,2-丙二醇,交联剂为二乙二醇丙烯酸酯,引发剂催化剂为过氧化苯甲酰-N,N-二甲基苯胺,分散剂采用聚乙烯比咯烷酮。制备出不同固相含量的悬浮液,经过凝胶成形与烧结,得到铜锡烧结多孔材料。探讨了坯体的性能、烧结过程中的收缩率、孔隙率、显微结构和力学性能。结果表明：经过脱模干燥后的坯体抗弯强度最大能达到12.76 MPa,坯体中的金属粉末颗粒均匀分散在有机三维骨架中,对于烧结多孔材料,随着固相含量的增加,烧结体密度增大,烧结收缩率降低,抗压性能提高。烧结试样孔隙率在20%～40%之间,烧结收缩率小于12%,抗弯强度最大为240 MPa,制备的烧结多孔材料孔隙分布均一、能制备复杂形状的部件。

Influence of solidification mode on pore structure of directionally solidified porous Cu-Mn alloy

By the directional solidification of metal-gas eutectic method（GASAR）,porous Cu-Mn alloy with oriented pores was fabricated successfully.The variation of pore structure was studied by experiments.The results show that the pore structure is primarily dependent on the solidification mode（planar,columnar cellular,columnar dendritic,equiaxed dendritic）,which is controlled by the solidification process.By numerical simulation,it is noted that along with solidification,the solidification mode of the alloy transforms from cellular to columnar dendritic and finally to equiaxed dendritic.Through increasing melt temperature and mold preheating,the range of equiaxed dendrite could be decreased,which helps to extend the region of oriented pore structure.

烧结工艺对多孔Ti-5Cu合金微观结构和力学性能的影响

以40%球形硬脂酸为占位剂,应用粉末冶金法制备出具有各向异性多孔结构的多孔Ti-5Cu合金,并研究了烧结工艺对多孔Ti-5Cu合金微观结构和力学性能的影响。结果表明烧结温度和保温时间对制备出的多孔Ti-5Cu合金的相组成没有明显影响,但对其微观结构和力学性能有较大影响。在900℃保温2h制备出孔结构和力学性能较佳的多孔Ti-5Cu合金,其孔隙率为68.25%,抗压强度为89.00MPa,弹性模量为3.79GPa,与人体骨的力学性能相近,有潜力用作骨修复材料。

Effect of heat treatment of Mn-Cu precursors on morphology of dealloyed nanoporous copper

Nanoporous copper with nano-scale pore size was synthesized by dealloying Mn-Cu precursor alloy using a free corrosion method. The effects of heat treatment of Mn-Cu precursors on alloy phase, morphology and composition of the resultant nanoporous copper were investigated. It is revealed that the compositions distribute homogeneously in the bulk Mn-Cu precursors, which consequently results in a more fully dealloying for forming nanoporous copper. The alloy phase changes from Cuo.a9Mno.51 and Cuo.21Mno.79 of non-thermally treated precursor to Cuo.33Mn0.67 of heat treated alloy. The residual Mn content in nanoporous copper is decreased from 12.97% to 2.04% （molar fraction） made from the precursor without and with 95 h heat treatment. The typical pore shape of nanoporous copper prepared by dealloying the precursor without the heat treatment is divided into two different zones： the uniform bi-continuous structure zone and the blurry or no pore structure zone. Nanoporous copper is of a uniform sponge-like morphology made from the heat-treated precursor, and the average ligament diameter is 40 nm, far smaller than that from the non-thermally treated precursor, in which the average ligament diameter is estimated to be about 70 nm.

Li_(x)Cu alloy nanowires nested in Ni foam for highly stable Li metal composite anode

Porous metal architectures are widely adopted as three-dimensional conducting scaffolds for constructing Li metal composite anodes,whereas their macropores hinder their practical application due to limited surface area and large pore size of few hundred micrometers.In this work,a network of Li_(x)Cu solid solution alloy nanowires is in situ formed via infiltrating molten Li-Cu alloy into Ni foam and subsequent cooling treatment,whereby a three-component composite anode consisting of Li metal,Li_(x)Cu alloy,and Ni foam is fabricated.The Li_(x)Cu nanowires nested as secondary frame split the macropores into micropores,enlarging the active surface area and inducing uniform Li deposition significantly.The lithiophilicity of the alloy wires and the shrunken void size built by the hierarchical architecture can further tune the nucleation and growth behavior of Li.The multiscale synergetic effect between the primary and secondary scaffold guarantees the composite anode sheet with extraordinarily long-term cycling stability even under high current rates.

Room-temperature liquid metal synthesis of nanoporous copper-indium heterostructures for efficient carbon dioxide reduction to syngas

Nanoporous metals show promising performances in electrochemical catalysis.In this paper,we report a self-supporting bimetallic porous heterogeneous indium/copper structure synthesized with a eutectic gallium-indium(EGaIn)material on a copper substrate.This nanoporous copper-indium heterostructure catalyst exhibits excellent performance in the reduction of carbon dioxide to syngas.The ratio of H_(2)/CO is tunable from 0.47 to 2.0 by changing working potentials.The catalyst is highly stable,showing 96%maintenance of the current density after a 70-h continuous test.Density functional theory calculations reveal that the indium/copper interface induces charge redistribution within the copper surface,leading to the formation of two distinct active sites,namely,Cu^(δ)and Cu0,and enabling a high-performance generation of CO and H_(2).This work provides a new strategy for obtaining self-supporting nanoporous metal electrode catalysts.