SiCp/AZ31镁基纳米复合材料的高能超声制备及性能

文章采用自行设计的高能超声装置制备SiCp/AZ31镁基纳米复合材料,并对制备的复合材料进行显微组织观察和力学性能测试。实验结果表明,高能超声波能使纳米SiCp在镁合金熔体中均匀分散,复合材料抗拉强度和屈服强度都比基体有较大提高,并能保持较高的延伸率。另外,对高能超声波制备金属基复合材料的分散机理,以及SiCp增强镁基纳米复合材料的增强机制,进行了初步探讨。     

SiC_p/AZ91镁基复合材料的热挤压

采用搅拌铸造法制备SiC体积分数为5%、10%和15%的颗粒增强AZ91镁基复合材料（SiCp/AZ91）。复合材料经过T4处理后,于350°C以固定挤压比12：1进行热挤压。在铸态复合材料中,颗粒在晶间微观区域发生偏聚。热挤压基本上消除了这种偏聚并有效地改善颗粒分布。另外,热挤压有效地细化基体的晶粒。结果表明：热挤压明显提高复合材料的力学性能。在挤压态复合材料中,随着SiC颗粒含量的升高,基体的晶粒尺寸减小,强度和弹性模量升高,但是伸长率降低。     

Aging behavior of nano-SiCp reinforced AZ61 magnesium matrix composites

The mechanical properties of magnesium matrix composties can be further improved by aging treatment.To study the aging behavior of SiC particles reinforced AZ61 magnesium matrix composites fabricated by ultrasonic method,an investigation has been undertaken by means of Vickers hardness measurement,scanning electron microscopy (SEM) and energy spectrum analyzing apparatus.The box-type heat treatment furnace was used in the study.The results showed that no discontinuous cellular precipitation is observed at the grain boundaries in the magnesium matrix of the composite while the Mg17Al12 preferentially precipitates in the matrix.The time to reach the peak hardness for AZ61 alloy or SiCp/AZ61 magnesium matrix composites is reduced with the increase of aging temperature.At the same temperature,the composite exhibit an accelerated aging manner but lower aging efficiency,compared with the unreinforced matrix alloy.The microhardness of the composite is higher than that of the unreinforced matrix alloy,because that the SiC particles distributes homogeneously in the matrix alloy under the ultrasonic processing condition.     

粒度组成对高体积分数SiC_p/Al复合材料性能的影响

采用凝胶注模法制备SiC预制件用于无压熔渗液态铝合金实现60～67 vol%SiCp/Al复合材料的近净成形制备,研究了碳化硅颗粒级配及热处理对复合材料力学和热学性能的影响.结果表明:不同粒度的SiC粉体在铝基体中分布均匀,无明显偏聚现象;采用较细的SiC颗粒级配和退火处理都能有效提高复合材料强度;粗颗粒级配能增大SiC在复合材料中的体积分数,有利于导热性能的提高和热膨胀系数的降低;SiCp/Al复合材料抗弯强度介于240～365 MPa,室温时热导率介于122～175 W·m-1·℃-1.之间,室温至250℃的平均线热膨胀系数小于7.5×10-6℃-1,满足电子封装的性能要求.     

SiC颗粒氧化行为及SiCp/铝基复合材料界面特征

界面反应和界面产物对SiCp/Al基复合材料的性能具有重要影响。对SiCp 的高温氧化行为进行了试验研究。结果表明 :SiCp 氧化起始温度为 80 0～ 85 0℃ ,其氧化增量和氧化产物SiO2 的体积分数及厚度与高温氧化处理的保温时间呈抛物线关系。以氧化处理的SiCp 为增强体 ,含Mg铝合金为基体 ,通过挤压铸造工艺制备复合材料。利用TEM和FE TEM对所得的复合材料界面进行观察 ,结果表明 ,在SiCp 表面形成了一定数量的尖晶石(MgAl2 O4 ) ,其数量和尺寸与Mg含量有关。由此 ,通过控制SiCp 的氧化处理工艺参数和基体合金成分 ,可以实现对SiCp/Al基复合材料界面反应及产物的控制     

Microstructures and mechanical properties of Al 2519 matrix composites reinforced with Ti-coated SiC particles

Ti-coated SiC_p particles were developed by vacuum evaporation with Ti to improve the interfacial bonding of SiC_p/Al composites. Ti-coated SiC particles and uncoated SiC particles reinforced Al 2519 matrix composites were prepared by hot pressing, hot extrusion and heat treatment. The influence of Ti coating on microstructure and mechanical properties of the composites was analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that the densely deposited Ti coating reacts with SiC particles to form TiC and Ti₅Si₃ phases at the interface. Ti-coated SiC particle reinforced composite exhibits uniformity and compactness compared to the composite reinforced with uncoated SiC particles. The microstructure, relative density and mechanical properties of the composite are significantly improved. When the volume fraction is 15%, the hardness, fracture strain and tensile strength of the SiC_p reinforced Al 2519 composite after Ti plating are optimized, which are HB 138.5, 4.02% and 455 MPa, respectively.     

铸造ZL101A／SiCp复合材料的研究

采用真空搅拌复合工艺制备了铸造ZL101A／SiC复合材料,研究了变质和细化处理对复合材料组织的影响。结果表明：变质和细化处理铸造 ZL101A／SiC复合材料制备工艺的重要处理措施,可明显改善复合材料的组织。利用透射电镜对AL／SiC界面特征及界面反应进行分析,同时对该复合材料的铸造性能（熔体合金流动性能、线收缩、体收缩和热裂倾向）以及力学和物理性能进行了测试。     

Microstructure and properties of mechanical alloying particles reinforced aluminum matrix composites prepared by semisolid stirring pouring method

Aluminum matrix composites reinforced with mechanical alloying particles(SiC_p) were fabricated by the semisolid stirring pouring method. The inf luence of mechanical alloying particles and Mg on the microstructure and mechanical properties of the composites was investigated by means of optical microscopy(OM), X-ray diffraction scanning(XRD), electron microscopy(SEM) and energy dispersive spectroscopy(EDS). Results show that the addition of Mg converts the agglomerate mechanical al oying particles in ZL101 matrix composites into dispersed distribution in ZL101-Mg matrix composites, large matrix grains into f ine equiaxed matrix grains, and eutectic phase into f ine particles. So the mechanical properties of ZL101-Mg matrix composites are better than those of ZL101 matrix composites. The mechanical properties of ZL101/ZL101-Mg matrix composites are gradually increased with the increase of the volume fraction of mechanical alloying particles. When the volume fraction of mechanical alloying particles is 3%, the Vickers hardness and ultimate tensile strength of the ZL101/ZL101-Mg matrix composites reach their maximum values.     

SiC／AZ61镁基复合材料蠕变性能的研究

采用搅熔铸造法制备碳化硅颗粒增强镁基复合材料SiC／AZ61,通过动态机械热分析、显微组织观察和XRD衍射分析了其蠕变性能。结果表明：碳化硅颗粒的加入细化了晶粒,SiC大多分布在晶界处,颗粒镁基复合材料的蠕变性能与AZ61合金相比得到了显著的改善。蠕变性能的提高主要因为高温时具有高的热稳定性的SiC颗粒取代晶界处高温下易软化的8相（Mg17Al22）钉扎晶界,阻止了晶界的交滑移和位错的攀移。     

喷射成形SiC颗粒增强Al—Mg基复合材料的性能与组织研究

采用多种实验方法，对喷射成形SiC颗粒（SiCp）增强Al-Mg基复合材料的性能与组织进行了研究。结果表明，实验用材料中，SiCp分布不均匀，大部分集中于晶界上；并存在较严重的缩孔，它们是导致材料性能降低的主要原因。     

高阻尼AA6061/SiCp/石墨复合材料的制备与性能

介绍采用粉末冶金法制备ＡＡ６０６１／ＳｉＣｐ／石墨混杂金属基复合材料的工艺过程,并对复合材料的力学和阻尼性能进行了初步探讨。粉末冶金法制备的ＡＡ６０６１／ＳｉＣｐ／石墨混杂金属基复合材料中增强增阻颗粒分布均匀,其体积分数可精确控制,加之制备温度低,可避免有害的界面反应。ＳｉＣ颗粒作为增强剂能够增加复合材料的刚度和强度,而石墨颗粒为增阻剂可以提高复合材料的阻尼特性。试验结果表明,能够应用粉末冶金法制     

PREPARATION OF 6066 Al/SiC_p( Gr) COMPOSITES BY MULTI-LAYER SPRAY DEPOSITION

ＰＲＥＰＡＲＡＴＩＯＮＯＦ６０６６Ａｌ／ＳｉＣ_ｐ（＋Ｇｒ）ＣＯＭＰＯＳＩＴＥＳＢＹＭＵＬＴＩ－ＬＡＹＥＲＳＰＲＡＹＤＥＰＯＳＩＴＩＯＮ￥ＣｈｅｎＺｈｅｎｈｕａ；ＺｈａｎｇＨａｏ；ＣｈｅｎＧａｎｇ；ＬｉｕＱｉｕｌｉｎ；ＳｕｎＺｈａｎｇｍｉｎｇ；Ｙａｎ?..     

Deformation behavior of SiC particle reinforced Al matrix composites based on EMA model

Effects of the matrix properties,particle size distribution and interfacial matrix failure on the elastoplastic deformationbehavior in Al matrix composites reinforced by SiC particles with an average size of 5μm and volume fraction of 12%werequantitatively calculated by using the expanded effective assumption(EMA)model.The particle size distribution naturally bringsabout the variation of matrix properties and the interfacial matrix failure due to the presence of SiC particles.The theoretical resultscoincide well with those of the experiment.The current research indicates that the load transfer between matrix and reinforcements,grain refinement in matrix,and enhanced dislocation density originated from the thermal mismatch between SiC particles and Almatrix increase the flow stress of the composites,but the interfacial matrix failure is opposite.It also proves that the load transfer,grain refinement and dislocation strengthening are the main strengthening mechanisms,and the interfacial matrix failure and ductilefracture of matrix are the dominating fracture modes in the composites.The mechanical properties of the composites strongly dependon the metal matrix.     

原位反应热压复合SiCP/MoSi2的显微结构与力学性能

以Mo粉、Si粉和C粉为原料，采用湿法混合和原位反应高温热压一次复合工艺制备了不同配比的SiCp/MoSi2复合材料，研究了该种工艺原位生成的SiC颗粒对MoSi2基体显微结构和室温力学性能的影响。结果表明：原位反应生成的适量SiC颗粒可以细化基体晶粒，改善其力学性能，与同样工艺下制备的纯MoSi2相比，含40vol%SiCp的SiCp/MoSi2复合材料室温抗弯强度是其3.4倍，含50vol%SiCp的SiCp/MoSi2复合材料室温断裂韧性是纯MoSi2的1.5倍；该种工艺的强化机制为细晶强化和弥散强化，韧化机制为细晶韧化。     

SiC颗粒增强体对铝基复合材料微弧氧化膜生长的影响

用微弧氧化方法在SiCp／2024铝基复合材料表面沉积出较厚的陶瓷膜，测定了陶瓷膜的生长曲线和相组成，提出了金属基复合材料微弧氧化膜生长模型．结果表明，微弧放电烧结作用下，膜层内SiCp增强体大部分已被熔化并氧化，只有少数残余的SiCp颗粒仍然保留在靠近界面的膜层内．SiCp增强体阻碍了微弧氧化膜的生长，但它并未破坏微弧氧化膜的完整性，这同铝基复合材料阳极氧化膜结构完全不同．     

Analysis of Microstructures and Mechanical Properties of Particle Reinforced AlSi7Mg2 Matrix Composite Materials

The present study examined the microstructures and mechanical properties (tensile and impact strength, hardness) of selected metal matrix composite materials. SiCp reinforced AlSi7Mg2 matrix composites were produced using gravity and squeeze casting methods and subsequently T6 heat treated. Some of the squeeze casted composites were shaped by extrusion. The extrusion generated an equiaxed matrix structure and SiCp caused a homogeneous distribution. The quasi absence of porosity in the squeeze casted composites led to improved mechanical properties. Whereas an increase in the SiCp ratio resulted in an increase of the tensile strength, it led to a decrease of the impact strength values. The enhancement of the mechanical properties following an applied heat treatment was better for materials shaped by extrusion.     

SiC_p/Al电子封装材料与陶瓷元件浸渗连接机理研究

分别将陶瓷元件嵌入凝胶注模成型后的SiC预制型中,再采用气压浸渗T艺制备高体积分数SiCp/Al复合材料的同时,实现了复合材料与元件的原位连接.采用SEM、EDS和XRD等分析了连接界面的显微组织及界面反应,结果表明:SiCp/AI与元件间的界面反应产物由MgAl204和Mg3Al2(SiO4)3等组成,界面反应层厚度约2～3μm,产物生成量主要由Al合金中的Mg、元件中SiO2含量等因素决定;SiCp/Al复合材料与Al2O3元件通过气压浸渗可以实现有效的反应连接.     

Effect of Particle Size on the Microstructures and Mechanical Properties of SiC-Reinforced Pure Aluminum Composites

This article examined the effects of particle size and extrusion on the microstructures and mechanical properties of SiC particle-reinforced pure aluminum composites produced by powder metallurgy method. It has been shown that both particle size and extrusion have important effects on the microstructures and mechanical properties of the composites. The SiC particles distribute more uniformly when the ratio of the matrix powder size and SiC particle size approaches unity, and the smaller-sized SiC particles tend to cluster easily. The voids are found to coexist with the clustered and large-sized SiC particles, and they significantly decrease the density and mechanical properties of the composites. Extrusion can redistribute the SiC particles in the matrix and decrease the number of pores, thus make the SiC particles distribute more uniformly in the matrix, and enhance the interfacial bonding strength. The decrease in the SiC particle size improves the tensile strength and yield strength, but decreases the ductility of the composites.     

Influence of Reinforcement Content and Matrix Composition on the Oxidation Resistance of Aluminum-Matrix Composites (A3xx.x/SiCp)

A study was made on the influence of the SiCp proportion and the matrix concentration of four composites (A360/SiC/10p, A360/SiC/20p, A380/SiC/10p, A380/SiC/20p) on their oxidation behavior. Gravimetric tests were used in a kinetics study of the corrosion process at different temperatures (350, 400, 450, and 500°C). The influence of corrosion on mechanical properties was evaluated by hardness measurements. The nature of corrosion products and the influence of the microstructure on the morphology and growth of the oxidation layer were analyzed by SEM and low-angle XRD. The extent of the damage due to oxidation for Al/SiCp composites increases with the SiCp concentration due to the increase of nucleation sites. One of these nucleation sites is in the interface region between the matrix and the particles. Oxidation was influenced more by the percentage of alloy elements in the matrix than by the proportion of SiCp reinforcement. The presence of Cu and Ni in the matrix favors the oxidation process through the formation of different intermetallic compounds.     

纳米SiC颗粒增强ADC12铝基复合材料的制备及性能

采用机械搅拌和超声分散相结合的方法制备出了纳米SiC颗粒增强ADC12铝合金基复合材料,并对制备出的复合材料进行微观结构分析和力学性能测试.结果表明,与基体合金相比,当纳米SiC颗粒的含量为2.0%时,所制得的复合材料的抗拉强度、弹性模量、断面收缩率及硬度分别提高23%、43%、160%和7.4%.用扫描电镜对试样拉伸断口的形貌和SiC颗粒的分散情况进行观察,发现纳米SiC颗粒在基体内呈均匀的弥散分布,没有发现大的团聚.同时,纳米SiC颗粒的均匀分布起到了阻碍或者阻止裂纹产生和扩展的作用.