Thermal and mechanical properties of Al/Al2O3 composites at elevated temperatures
Thermal and mechanical properties of Al/Al2O3 composites at elevated temperatures
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DOI：
10.1016/j.msea.2011.10.001
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发表时间：
2012
期刊：
影响因子：
6.4
通讯作者：
Pradeep Gudlur;A. Forness;J. Lentz;M. Radovic;A. Muliana
中科院分区：
文献类型：
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作者：
Pradeep Gudlur;A. Forness;J. Lentz;M. Radovic;A. Muliana
本研究的目的是确定相体积含量、加工条件、铝颗粒尺寸和孔隙率对氧化铝增强铝复合材料在25-450°C温度范围内的物理和热机械性能的影响。采用粉末冶金技术制备了氧化铝体积含量分别为0%、5%、10%、20%和25%的复合材料。制备了两种含有不同铝粉的复合材料：颗粒尺寸为7-15μm的复合材料A - 99.97%纯Al，颗粒尺寸为3-4.5μm的复合材料B - 97.5%纯Al粉。对于复合材料A和B，使用粒度<10μm的氧化铝粉末。对复合材料样品的孔隙率、相对密度和氧化铝相的分布进行了表征。使用共振超声光谱（罗斯）作为温度的函数的复合材料的弹性性能（杨氏模量和剪切模量），而热膨胀系数（CTE），在不同的温度下，使用热机械分析仪（TMA）确定。发现具有较小铝颗粒的复合材料（复合材料B）具有较高的相对密度值，因此具有较高的弹性模量，并且具有比具有较大铝颗粒的复合材料（复合材料A）低的CTE值。在所有情况下，增加氧化铝的体积含量增加了弹性模量并降低了复合材料的CTE。将测试温度从25 °C提高到450°C，显著降低了复合材料的弹性模量，而复合材料的CTE仅随温度略有变化。
The objective of this study is to determine the effects of phase volume content, processing conditions, the size of aluminum particles, and porosity, on the physical and thermo-mechanical properties of an alumina reinforced aluminum composite in 25–450°C temperature range. Composites with 0%, 5%, 10%, 20% and 25% volume contents of alumina are manufactured using powder metallurgy technique. Two types of composites with different aluminum powders were manufactured: composite A – 99.97% pure Al with 7–15μm particles, and composite B – 97.5% pure Al powder with 3–4.5μm particles. For both composites A and B, alumina powder with <10μm particle size was used. The composite samples were characterized for their porosity, relative density and distribution of the alumina phase. The elastic properties (Young's modulus and shear modulus) of the composites were determined using resonant ultrasound spectroscopy (RUS) as a function of temperature while the coefficient of thermal expansion (CTE) was determined at various temperatures using thermo mechanical analyzer (TMA). It was found that the composite with smaller aluminum (composites B) particles had higher values of the relative density and thus higher elastic moduli, and lower values of the CTE than the composites with larger aluminum particles (composites A). In all cases, increasing the volume contents of the alumina increases the elastic moduli and reduces the CTE of the composites. Increasing the testing temperature from 25 to 450°C, significantly reduces the elastic moduli of the composites, while the CTE the composites only slightly changes with temperatures.