12%SiCp/Al复合材料制备工艺及力学性能研究

对碳化硅颗粒进行表面氧化酸洗处理，采用粉末冶金加热挤压工艺制备了12％SiCp／Al（体积分数）复合材料。利用金相显微镜和电镜对微观组织进行了观测，拉伸试验测试复合材料的力学性能。试验结果表明：SiC颗粒在铝基体中分布比较均匀；T6热处理条件下12％SiCp／Al复合材料的屈服强度和抗拉强度分别约为472．4MPa、525．7MPa，伸长率为6．5％，弹性模量为92．7GPa。     

SiCp/Al复合材料的研究方法现状

SiC颗粒（SiCp）增强铝基复合材料因其制备工艺灵活，热物理性能优异及可设计性等许多独特的优点而具有很好的应用前景。本文综述了SiCp增强铝基复合材料的研究和进展，阐述并比较了几种该复合材料的制备工艺，包括搅拌铸造法、压力铸造法、无压渗透法、喷雾沉积法、离心铸造法和粉末冶金法等。     

熔体发泡法制备泡沫鋁的缺陷分析

以TiH2作发泡剂，采用熔体发泡法通过控制发泡温度、保温时间、搅拌速度、冷却方式及各种添加剂含量，成功制备出孔结构基本均匀，孔隙率为60％～85％、平均孔径〈3mm泡沫铝样品。重点分析了泡沫铝制备过程中对孔结构稳定性和均匀性影响因素，针对泡沫铝常见缺陷（缩孔、裂纹、局部大孔），出现的原因提出改进措施。     

自蔓延反应涂层法制备SiCp/Al复合材料及性能

对采用铝浴自蔓延反应涂层制备SiCp/Al复合材料的反应机理及与组织演变研究发现：在SiCp/Al表面形成TiC和Ti5Si3复合涂层，显著改善了SiCp与铝液的润湿性，凝固后的SiCp/Al复合材料经热挤压可进一步改善界面状态和界面结合。对它的力学性能和摩擦磨损性能研究表明：由于SiCp的加入对弹性模量的影响与其它方法制备的SiCp/Al复合材料相同，因此可通过降低反应程序，以便提高材料的力学性能。SiSp/Al复合材料摩擦性能主要取决于SiC颗粒的粒度及含量。     

高硅铝合金及颗粒增强铝基复合材料组织性能的探究

采用真空热压烧结工艺制备Al-30Si合金、30%Sip/Al、30%SiCp/2024Al、30%SiCp/6061Al(均为体积分数)复合材料,测定其热膨胀系数及力学性能。利用扫描电镜(SEM)、能谱仪(EDS)对其微观组织结构及断口形貌进行表征,探究了高硅铝合金及颗粒增强铝基复合材料的组织与性能,分析了材料的断裂机制。结果表明:SiCp/2024Al复合材料中SiC颗粒分布均匀,组织致密,综合性能好,热膨胀系数(CTE)为13.69×10-6/K,硬度达到134 HB,极限抗拉强度达353 MPa。SiCp/6061Al复合材料中SiC颗粒分布较均匀,界面结合较好,组织不够致密,有少许孔隙,性能较好。SiCp/6061Al和SiCp/2024Al复合材料的断裂方式都是界面基体的撕裂结合SiC颗粒的断裂。Sip/Al复合材料中Si颗粒分布较均匀,断裂方式为界面脱开,性能较差。Al-30Si合金在烧结过程中形成大量板条状的Si相,性能最差,断裂方式以合金撕裂为主。     

PCM法制备泡沫铝的研究现状及应用前景

论述了PCM法 (powder compacting melting) 制备泡沫铝的国内外研究现状,重点对该工艺参数对发泡过程的影响、发泡机理及泡沫铝复合结构进行了讨论,展望了PCM法制备泡沫铝的应用前景.     

碳化硅颗粒增强铝基复合材料的制备工艺进展

综述了碳化硅颗粒增强铝基复合材料(SiCp/Al基复合材料)的研究进展,重点阐述了SiCp/Al基复合材料的主要制备工艺,并在此基础上展望了其相关及后续工艺的研究方向.     

泡沫铝制备与其压缩性能研究

采用粉末致密化发泡（PCF）工艺制备了泡沫纯铝,对制备过程及影响孔结构的因素进行了分析.系统研究了压力、发泡温度、发泡时间、发泡剂含量和粒度对泡沫纯铝结构变化的影响规律,用自行设计的软件FoamScan对孔结构进行了描述.得出了试验条件下的优化工艺参数配置.进行了泡沫铝压缩性能测试,通过理论模型、性能测试数据作图对比的方法获得了孔隙率83%～87%泡沫纯铝的屈服强度表达式.确定了泡沫纯铝的制备工艺、结构、性能的相互关系.     

前驱体合金化方式对粉末冶金泡沫铝孔结构的影响

以Al Si11合金为对象,选取了预合金化的粉末和元素混合粉末作为前驱体的原料,以Ti H2粉末为发泡剂,采用粉末冷等静压、真空热除气、热挤压成形等工艺制备前驱体、再次加热发泡成型的方法制备了不同时间状态的一系列泡沫铝试样;对系列试样的孔隙率、孔径及其分布、孔形貌等参数的演变规律进行了对比研究;对孔壁微观组织进行了金相表征。结果表明,预合金粉前驱体制备的泡沫铝试样的最大孔隙率为72%,平均孔径为0.59~3.38 mm,孔径分布不均匀;气孔演化过程经历了气孔形核、气孔长大和快速合并阶段,发泡后期出现严重排液现象。元素混合粉前驱体制备的泡沫铝试样的最大孔隙率为84%,平均孔径为0.58~1.99 mm,孔径分布较为均匀;气孔经历了形核、快速合并长大和气孔缓速合并3个阶段。二者相比,元素混合粉前驱体的可发泡性更好、气孔稳定性更好;结合组织分析可知,前驱体中AlSi组织特征(尤其是界面形态)的差异从本质上决定了合金的熔化和凝固行为,进而对气孔形核和演化产生了较大的影响。     

粉末冶金法制备泡沫Al的工艺研究

系统研究了粉末冶金法制备泡沫舢的工艺条件。通过粉末冶金法制备出了孔隙度为50％～85％，孔径2～5mm的闭孔泡沫Al。讨论了发泡工艺参数对泡沫Al结构的影响。依据试验结果，我们获得的最佳发泡工艺为：发泡温度720℃，发泡时间12min，发泡剂的质量分数为2％。在此条件下可制备出孔隙度大于80％，孔径较均匀的泡沫Al材料。     

熔体发泡法制备稀土泡沫铝合金试验研究

简述了熔体发泡法制备稀土泡沫铝合金的发泡机理,主要讨论了温度、搅拌时间、发泡剂含量等对其发泡性能的影响及微量稀土元素在泡沫铝合金中的作用,通过实验得出最佳的工艺条件。     

泡沫铝的连续制备

泡沫铝材是一种由气体和金属复合而成的新型材料,具有优异的综合性能,在各个领域有着广泛的应用前景.本文系统地阐述了采用二次发泡法连续制备泡沫铝的工艺过程和试验装置.     

Fabrication of Two-Layered Aluminum Foam Having Layers with Closed-Cell and Open-Cell Pores

Two-layered aluminum foam having layers with both closed-cell and open-cell pores was fabricated using the precursor foaming process and the sintering dissolution process. It was found that a two-layered Al foam with different pore structures but similar compression properties in each layer can be obtained. This foam is expected to have a region with superior thermal insulation and a region with superior heat release properties.     

泡沫铝及其三明治结构累积叠轧制备

通过累积叠轧法制备泡沫铝.采用称重法研究泡沫铝孔隙结构,利用光学显微镜观察泡沫铝孔隙形貌.发现以TiH₂为发泡介质,当发泡温度660~680℃和发泡时间6~10 min时,利用累积叠轧法制备泡沫铝的孔隙结构特性最好.发泡温度和发泡时间的最佳值与发泡剂用量有关,TiH₂质量分数为1.5%,在670℃发泡8 min,泡沫铝的孔隙率可达到42%,孔径为0.43 mm.以制备的泡沫铝为夹芯,通过轧制复合制备了TC4钛合金/泡沫铝芯和1Cr18Ni9Ti不锈钢/泡沫铝芯三明治板.利用光学显微镜和能谱仪研究了三明治板的界面.面板与芯板间的化合反应形成了界面的反应层,界面实现了冶金结合.      

Effect of Sn on the Dehydrogenation Process of TiH2 in Al Foams

The study of the dehydrogenation process of TiH₂ in aluminum foams produced by the powder metallurgy technique is essential to understanding its foaming behavior. Tin was added to the Al foam to modify the dehydrogenation process and stabilize the foam. A gradual decomposition and more retention of hydrogen gas can be achieved with Sn addition resulting in a gradual and larger expansion of the foam.     

Processing and Stability of LM25/SiCP Composite Foams

A simple method of metal foam production is to introduce a blowing agent (e.g. TiH₂) into an aluminium melt containing foam stabilisers such as oxides (usually Ca-based) and/or particles (e.g. SiC, Al₂O₃). In this work, Al/SiC composites (in-house and commercial Duralcan) [both of them with LM25 matrix (Al?C7Si?C0.3Mg)] containing particles of various sizes and contents were foamed at different temperatures using TiH₂. Foamability is characterised through their expansion and collapse. It is observed that high expansions and good quality foams could be obtained upon manipulating SiC particle size and content. However, irrespective of particle size/vol.% combination, significant effect of foaming temperature is noticed on the fundamental stability of the liquid foam until solidification. Both cell size and foam density varied along the ingot height. The distribution of SiC_P within the cell wall is random with no preferential segregation to gas/metal interface. The evolution of foam, and the role of SiC on foam stability are discussed based on macro and cell wall microstructural results.     

Fabrication of foamable precursors by powder compression and induction heating process

In the powder compact melting technique, metallic foams are fabricated by heating a precursor, thus initiating cell growth and foam formation. Proper precursor fabrication is very important because the density distribution after foaming and the foamability are determined during the precursor-fabrication process. The fabrication of the precursor has to be performed very carefully because any residual porosity or other defects will lead to poor results in further processing. In order to evaluate the effect of the compaction parameters on the kinetics of the foaming process, a series of experiments were performed. In this study, 6061 aluminum foams having a closed-cell structure were fabricated by the powder compact method and an induction heating process. An induction coil was designed to obtain a uniform temperature distribution over the entire cross-sectional area of the precursor. To establish the foamable precursor fabrication conditions, the effects of process parameters such as titanium hydride content (0.1 to 1.5 wt pct) and the compression pressure of the foamable precursor (50 to 150 kN) on the pore morphology were investigated.     

Fabrication of Al-3.7?Pct Si-0.18?Pct Mg Foam Strengthened by AlN Particle Dispersion and its Compressive Properties

Al-3.7 pct Si-0.18 pct Mg foams strengthened by AlN particle dispersion were prepared by a melt foaming method, and the effect of foaming temperature on the foaming behavior was investigated. Al-3.7 pct Si-0.18 pct Mg alloy containing AlN particles was prepared by noncompressive infiltration of Al powder compacts with molten Al alloy in nitrogen atmosphere, and it was foamed at different foaming temperatures ranging from 1023 to 1173 K. The porosity of prepared foam decreases and the pore structure becomes homogeneous with increasing foaming temperature. When the foaming temperature is higher than 1123 K, homogeneous pores are formed in the prepared ingot without using oxide particles and metallic calcium granules, which are usually used for stabilizing a foaming process. This stabilization of the foaming at high temperatures is possibly caused by Al₃Ti intermetallic compounds formed at high temperature and AlN particles. Compression tests for the prepared foams revealed that the absorbed energy per unit mass of prepared Al-3.7 pct Si-0.18 pct Mg foam is higher than those of aluminum foams strengthened by alloying or dispersion of reinforcements. It is remarkable that the oscillation in stress, which usually appears in strengthened aluminum foams, does not appear in the plateau stress region of the present Al-3.7 pct Si-0.18 pct Mg foam. The homogeneity in cell walls and pore morphology due to the stabilization of pore formation and growth by AlN and Al₃Ti particles is a possible cause of this smooth plateau stress region.     

LF埋弧精炼渣发泡剂实验研究

实验了多种物质作为发泡剂的使用效果。实验结果表明，碳酸钙作为LF精炼渣的发泡剂是适合的，SiC单独使用效果不佳，但作为复合发泡剂的组成可以明显改善发泡过程。发泡剂的粒度对泡沫渣的形成有重要作用，不同粒度的发泡剂混合使用可以得到较理想的结果。