共查询到19条相似文献,搜索用时 612 毫秒
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设计并采用真空气压浸渗法制备了不同颗粒尺寸的高体积分数SiCp/AZ91D镁基复合材料,研究了颗粒尺寸对镁基复合材料热膨胀性能的影响.结果表明,改变颗粒尺寸是调节镁基复合材料热膨胀性能的一种非常有效的手段.相同体积分数复合材料的热膨胀系数随颗粒尺寸的减小而逐渐降低,不同体积分数的SiCp复合材料的热膨胀系数与复合材料的界面面积成反比关系;减小颗粒尺寸与提高颗粒体积分数一样,能有效降低复合材料的热膨胀系数;颗粒尺寸对镁基复合材料热膨胀性能的作用机制主要是通过复合材料的界面面积、致密度及其镁基体的位错密度来实现的. 相似文献
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采用气压浸渗方法制备了SiCP/Al(SiC颗粒增强铝基复合材料)。研究了复合材料的工程热膨胀系数CTE和物理CTE随体积分数的变化关系。结果表明,随着SiC颗粒体积分数的增加,复合材料的工程CTE减小,物理CTE也减小。相比双尺寸SiC,/Al,单尺寸颗粒的SiCP/Al物理CTE曲线随温度增长不规则,这可以归结于SiC颗粒与基体合金接触表面积较小. 相似文献
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SiCp/Mg(AZ81)镁基复合材料制备工艺的优化 总被引:6,自引:1,他引:5
研究了不同铸造工艺条件下镁基复合材料的组织结构,并对其气孔率进行了测定。结果表明,随着搅拌温度的提高,复合材料的气孔率上升。当颗粒尺寸一定时,复合材料的气孔率随颗粒体积分数的增加而增加;当颗粒体积分数一定时,复合材料的气孔率随颗粒尺寸的增大而减少。搅熔铸造法制备的复合材料在颗粒分布及气孔含量方面均优于半固态搅拌铸造法和全液态搅拌铸造法。 相似文献
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建立了TiC/AZ91镁基复合材料的三维有限元模型,通过ABAQUS有限元软件研究了拉伸过程中TiC增强颗粒尺寸对TiC/AZ91镁基复合材料力学性能的影响。结果表明:对于单一尺寸颗粒TiC/AZ91镁基复合材料,TiC颗粒的失效比随着TiC颗粒尺寸的减小而增大,复合材料的屈服强度随着TiC颗粒尺寸的增大而减小;对于混杂尺寸颗粒的TiC/AZ91镁基复合材料,复合材料所受最大应力分布在该材料的小尺寸颗粒处,小尺寸颗粒所占比例越大,颗粒失效比越高。 相似文献
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采用AlSiTiCrNiCu高熵合金颗粒(HEA_p)作为增强相增强铝合金,研究高熵合金颗粒体积分数和烧结温度对HEA_p/6061Al复合材料热膨胀系数(CTE)的影响。结果表明:25~100℃时,6061Al合金和AlSiTiCrNiCu高熵合金(HEA)的热膨胀系数分别为23.04×10~(-6)/℃和9.85×10~(-6)/℃;随着高熵合金颗粒体积分数的增高,HEA_p/6061Al复合材料的热膨胀系数明显降低。当保持高熵合金颗粒体积分数不变时,随着温度的升高,HEA_p/6061Al复合材料的热膨胀系数呈现出先增大后保持不变的规律。 相似文献
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《Acta Materialia》2003,51(11):3145-3156
The thermal response and the coefficient of thermal expansion (CTE) of aluminium matrix composites having high volume fractions of SiC particulate have been investigated. The composites were produced by infiltrating liquid aluminium into preforms made either from a single particle size, or by mixing and packing SiC particulate of two largely different average diameters (170 and 16 μm, respectively). The experimental results for composites with a single particle size indicate that the hysteresis in the thermal strain response curves is proportional to the square root of the particle surface area per unit volume of metal matrix, in agreement with current theories. Instead, no simple relationship is found between the hysteresis and any of the system parameters for composites with bimodal particle distributions. On the other hand, the overall CTE is shown to be mainly determined by the composite compactness or total particle volume fraction; neither the particle average size nor the particle size distribution seem to affect the overall CTE. This result is in full agreement with published numerical results obtained from finite element analyses of the effective CTE of aluminum matrix composites. Our results also indicate that the CTE varies with particle volume fraction at a pace higher than predicted by theory. 相似文献
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采用气压浸渗法制备中体积分数电子封装用 Al/Si/SiC 复合材料。在保证加工性能的前提下,用与 Si 颗粒相同尺寸(13 μm)的 SiC 替代相同体积分数的硅颗粒制得复合材料,并研究其显微组织与性能。结果显示,颗粒分布均匀,未发现明显的孔洞。随着 SiC 的加入,强度和热导率将得到明显提高,但热膨胀系数变化较小,对使用影响也不大。讨论几种用于预测材料热学性能的模型。新的当量有效热导被引入后,H-J 模型将适用于混杂和多颗粒尺寸分布的情况。 相似文献
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采用热压烧结工艺制备了 Ti Cp/ W系列复合材料 ,分析测试了温度和 Ti C含量对复合材料的热物理性能的影响规律。结果表明 :随着温度的升高 ,复合材料的定压比热和平均线膨胀系数单调增大 ,热扩散率稍有减小 ,热导率略有增大。随 Ti C含量的增加 ,复合材料的定压比热和平均线膨胀系数线性增大 ,基本满足混合定律。热扩散率和热导率对材料的组织结构比较敏感 ,二者均随 Ti C含量的增加而急剧减小。热导率的实测值大大低于理论计算值 ,这主要是由晶界和孔洞等缺陷对导热粒子的强烈散射作用造成的。 相似文献
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A finite element analysis was carried out on the development of residual stresses during the cooling process from the fabrication temperature in the SiCp reinforced AI matrix composites. In the simulation, the two-dimensional and random distribution multi-particle unit cell model and plane strain conditions were used. By incorporating the Taylor-based nonlocal plasticity theory, the effect of particle size on the nature, magnitude and distribution of residual stresses of the composites was studied. The magnitude thermal-stress-induced plastic deformation during cooling was also calculated. The results show similarities in the patterns of thermal residual stress and strain distributions for all ranges of particle size. However, they show differences in magnitude of thermal residual stress as a result of strain gradient effect. The average thermal residual stress increases with decreasing particle size, and the residual plastic strain decreases with decreasing particle size. 相似文献
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以硼质量分数为0.5%的Cu–B合金为金属基体以及平均粒径为500 μm的金刚石颗粒为增强体,采用气压熔渗法制备金刚石/Cu–B合金复合材料,研究气压参数对其组织结构和热物理性能的影响规律。结果表明:随着气压升高,金刚石与Cu–B合金之间的界面结合效果、导热性能均增强,热膨胀系数减小;当气压为10 MPa时,其界面结合效果最优,界面处生成的碳化物层将金刚石完全覆盖,且100 ℃时的样品热导率为680.3 W/(m·K),热膨胀系数为5.038×10?6 K?1,满足电子封装材料的热膨胀系数要求。 相似文献
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采用高温高压烧结工艺制备了金刚石体积分数为80%的金刚石-铜复合材料。研究了金刚石颗粒大小、烧结温度、烧结时间等因素对复合材料成分、界面状态和热导率的影响。结果表明:金刚石颗粒直径为80μm时,在高温高压条件下可获得热导率高达639 W.m-1.K-1的金刚石-铜复合材料。当金刚石体积分数一定时,存在一临界粒径,随金刚石颗粒直径增大复合材料热导率先增大后减小。恰当的烧结温度和时间有助于获得黏结良好的界面和高热导率。 相似文献
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Shanta Sastry M. Krishna Jayagopal Uchil 《Journal of Materials Engineering and Performance》2001,10(2):220-224
When the fabrication of a metal matrix composite (MMC) involves its cooling from a high temperature, plastic-elastic residual
deformation fields can be generated within and around the particle due to the differential thermal expansion between the particle
and matrix metal. The present investigation is concerned with the effect of thermal residual stresses on the thermal expansion
and damping behavior of aluminite particulate-reinforced ZA-27 alloy MMCs. Composites were prepared by the compocasting technique
with 1, 2, 3, and 4 wt.% of aluminite reinforcement. Thermal expansion and damping properties have been studied experimentally
as a function of temperature over a temperature range 30 to 300 °C both in the heating and cooling cycle. The thermal expansion
studies exhibited some residual strain, which increased with the increase in the weight percent of the reinforcement. The
damping capacity of both the composites and matrix alloy is found to increase with the increase in temperature during the
heating cycle, whereas in the cooling cycle, damping behavior exhibits a maximum, which becomes more pronounced with the increase
in the weight percentage of the reinforcement. The appearance of the maximum may be linked with dislocation generation and
motion as a result of plastic deformation of the matrix at the metal/reinforcement interface. This phenomenon is attributed
to the thermal stresses generated as a result of coefficient of thermal expansion (CTE) mismatch between the composite constituent
phases. The thermal stresses have been estimated in both the cases using simple models. 相似文献
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以SiC和镀钨金刚石增强体为原料制备预制体,通过气压浸渗技术在800 ℃,5 MPa条件下制备金刚石–SiC/Al复合材料。利用扫描电镜、红外热成像仪、激光导热仪等对复合材料性能进行分析,研究SiC和金刚石的含量与粒径比对复合材料构型的影响,从而优化复合材料导热性能。结果表明:在相同的SiC粒径下,金刚石体积分数的增加将使复合材料的导热性能明显提升。当金刚石体积分数为30%时,含F100 SiC的复合材料导热性能最佳,其热导率为344 W/(m?K)。当金刚石体积分数相同,粒径比从0.07增大到0.65时,复合材料导热性能依次提升;且在金刚石体积分数为15%时,复合材料的热导率增幅最大,从174 W/(m?K)增大到274 W/(m?K),增长了57%。通过改善金刚石–SiC/Al复合材料中增强体的含量和粒径比可以调控复合材料构型,充分发挥复合材料的导热潜力。 相似文献
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Zuzanka Trojanov Werner Riehemann Hans Ferkel Pavel Luk 《Journal of Alloys and Compounds》2000,310(1-2):396-399
Using internal friction measurement, changes in the microstructure of microcrystalline magnesium and magnesium with 3 vol.% of Al2O3 microparticles and nanoparticles, due to thermal treatment, have been investigated. Materials have been thermally treated at increasing temperature and then the amplitude dependence of the logarithmic decrement was measured at room temperature. The thermal treatment influences the amplitude-dependent component of the decrement in composite with nanoparticles while in composite with microparticles no influence has been estimated. Thermal stresses induced in the composites due to a difference between thermal expansion coefficient of matrix and ceramic particles may create new dislocations during the cooling from elevated temperatures. Density of new dislocations depends on the particle size. The thermal stresses can achieve yield stress in the matrix and micro-glide of newly created dislocations as well as their annihilation may occur. 相似文献