铝金属基复合材料Al6061/SiC_P表面稀土转化膜的研究

利用电化学方法评价了铝金属基复合材料 Al60 61 /Si CP表面稀土转化膜的抗腐蚀性能 ,膜的存在使腐蚀过程中的阴极反应和阳极反应同时减弱 ,腐蚀速率降低。利用扫描电镜 ( SEM)观察了稀土转化膜的表观形貌 ,膜是以球团状结构层层向外生长 ,最后完全覆盖基体表面。利用 X射线衍射 ( XRD)研究了膜的微观形态 ,膜是以非晶态形式存在。利用 X射线光电子能谱 ( XPS)分析了膜的成分 ,膜是由铈的氧化物和氢氧化物组成。

铝金属基复合材料表面稀土转化膜

介绍了铝金属基复合材料的发展情况及存在的腐蚀问题。详细评述 了铝金属基复合材料表面稀土转化膜在国内外的研究进展及现状，对未来这一技

碳化硅铝金属基复合材料

据报道，美国陶瓷工艺系统公司（CPS）在一些小型微处理器外壳和大型IGBT冷却座的冷却管结构中，集成应用了一种碳化硅铝（AlSiC）金属基复合材料。这种金属基复合材料在不锈钢冷却管或热交换器内壁制造过程中都可加入．以形成一体化冷却结构。这种集成了金属复合材料的冷却管不仅可提高冷却管的热特性．而且可降低冷却管与金属外壳结构之间的热阻力。

提高金属基复合材料制造效率的方法

基于美国底特律的公私营财团，面向未来轻量化创新中心（LIFT）和俄亥俄州梅菲尔德海茨Materion集团正在联手寻找高效率的制造运输部件轻质铝金属基复合材料（MMCs）的办法。他们与行业专家和大学研究人员进行为期两年的合作，

Effects of reinforcement on wear resistance of aluminum matrix composites

The effect of reinforcement on the wear mechanism of metal matrix composites （MMCs） was investigated by considering different parameters, such as sliding distance （6 km）, pressure （0.14-1.1 MPa） and sliding speed （230-1480 r/min）. The wear mechanisms of an MMC and the corresponding matrix material under similar experimental conditions were compared on a pin-on-disc wear machine. The pins were made of 6061 aluminum matrix alloy and 6061 aluminum matrix composite reinforced with 10% Al2O3 （volume fraciton） particles （6-18μm）. The disc was made of steel. The major findings are as follows： the MMC shows much higher wear resistance than the corresponding matrix material; unlike that of matrix material, the wear of MMC is very much linear and possible to predict easily; the wear mechanism is similar for both materials other than the three-body abrasion in the case of MMC; the reinforced particles resist the abrasion and restrict the deformation of MMCs which causes high resistance to wear. These results reveal the roles of the reinforcement particles on the wear resistance of MMCs and provide a useful guide for a better control of their wear.

Influence of rutile(TiO_2) content on wear and microhardness characteristics of aluminium-based hybrid composites synthesized by powder metallurgy

The effect of rutile（TiO_2） content on the wear and microhardness properties of aluminium（Al）-based hybrid composites was explored. The proposed content of TiO_2（0, 4%, 8%, 12%, mass fraction） was blended to Al-15% SiC composites through powder metallurgy（P/M） process. Wear test was conducted using pin-on-disc apparatus under dry sliding conditions. Fabricated preforms were characterized using X-ray diffractometer（XRD）, scanning electron microscope（SEM） and energy-dispersive X-ray spectrometer（EDS）. Optical micrographs of the composite preforms display uniform distribution of TiO_2 throughout the matrix. Quantitative results indicate that wear resistance and microhardness increase with the increase of TiO_2 content. SEM images unveil that high wear resistance is attributed to high dislocation density of deformed planes and high hardness of TiO_2. SEM images of wear debris display gradual reduction in mean size of debris when TiO_2 content increases. EDS spectra confirm the presence of oxide layer which obviously reduces the effective area of contact between the sliding surfaces thereby lowers the wear loss of composites. The observation concludes that delamination and adhesive wear are the predominant mechanisms.

Strengthening contributions in ultra-high strength cryorolled Al-4%Cu-3%TiB_2 in situ composite

Ultra-high strength Al alloy system was developed by cryorolling and the contribution of various strengthening mechanisms to the overall yield strength of the system was evaluated. Cryorolling of Al-4%Cu-3%TiB2 in situ composite followed by short annealing at 175 ℃ and ageing at 125℃ resulted in an ultra-high yield strength of about 800 MPa with 9%total elongation. The strengthening contributions form solid solution strengthening, grain refinement, dislocation strengthening, precipitation hardening and dispersion strengthening were evaluated using standard equations. It was estimated that the maximum contribution was from grain refinement due to cryorolling followed by precipitation and dispersion strengthening.

Combustion synthesis of FeAl−Al2O3 composites with TiB2 and TiC additions via metallothermic reduction of Fe2O3 and TiO2

Combustion synthesis involving metallothermic reduction of Fe2O3 and TiO2 was conducted in the mode of self-propagating high-temperature synthesis(SHS)to fabricate FeAl-based composites with dual ceramic phases,TiB2/Al2O3 and TiC/Al2O3.The reactant mixture included thermite reagents of 0.6Fe2O3+0.6TiO2+2Al,and elemental Fe,Al,boron,and carbon powders.The formation of xFeAl−0.6TiB2−Al2O3 composites with x=2.0−3.6 and yFeAl−0.6TiC−Al2O3 composites with y=1.8−2.75 was studied.The increase of FeAl causes a decrease in the reaction exothermicity,thus resulting in the existence of flammability limits of x=3.6 and y=2.75 for the SHS reactions.Based on combustion wave kinetics,the activation energies of Ea=97.1 and 101.1 kJ/mol are deduced for the metallothermic SHS reactions.XRD analyses confirm in situ formation of FeAl/TiB2/Al2O3 and FeAl/TiC/Al2O3 composites.SEM micrographs exhibit that FeAl is formed with a dense polycrystalline structure,and the ceramic phases,TiB2,TiC,and Al2O3,are micro-sized discrete particles.The synthesized FeAl−TiB2−Al2O3 and FeAl−TiC−Al2O3 composites exhibit the hardness ranging from 12.8 to 16.6 GPa and fracture toughness from 7.93 to 9.84 MPa·m1/2.

Effects of reciprocating extrusion process on mechanical properties ofAA 6061/SIC composites

A reciprocating extrusion （RE） process was used to improve the mechanical properties of Al-based composite manufactured using cast and powder metallurgy （PM）. AA 6063 cast and AA 6061 powders were used as the matrix materials, and the matrix was reinforced by 5% SiC （volume fraction） particles. The hardness and grain size of extruded samples decrease with increasing the number of extrusion pass, while the toughness and ductility increase. As the tensile strength of the samples decreases, the elongation of the extruded samples increases. Consequently, reciprocating extrusion is an effective method for improving the mechanical properties of metal matrix composites （MMC）.

压力容器的设计研究

压力容器广泛应用于各行业,如石油和天然气、化学工业、发电行业、食品行业等。压力容器的故障会对周围环境和行业发展产生不利影响,可能导致对生命和财产的损害。压力容器的设计取决于各种因素,如压力、温度、所选材料、腐蚀、载荷和许多其他参数,这主要取决于具体应用领域生产活动的要求。文章阐述了重型压力容器的轻量化设计、多层压力容器的耐高温高压设计、压力容器的材料优化设计和有限元法设计,以提高压力容器的安全性。