喷射共沉积6013Al/SiCp/Gr复合材料阻尼机制的研究

【作者】 杨会智；

【导师】 王西科；

【作者基本信息】 郑州大学 ， 材料加工工程， 2003， 硕士

【摘要】 本文采用喷射共沉积方法制备了6013Al／SiCp／Gr金属基复合材料(MMC)，通过改变淬火介质，较为系统地研究了五种热处理制度(炉冷、空冷、水冷、干冰冷及液氮冷)以及不同时效温度(120℃、150℃、170℃、190℃及210℃)对6013Al／SiCp／Gr MMC阻尼性能影响。另外，对出现在各热处理态试样中的内耗峰进行了比较和分析。 首先，对各热处理态试样进行了金相(OM)分析，并对原始样进行了X射线衍射(XRD)分析，接着测试了水淬试样在不同时效时间的显微硬度，还制备了原始样的电镜试样，并用透射电镜(TEM)进行了观察和分析。结果表明，此复合材料中SiC颗粒分布比较均匀，X射线衍射谱上有SiC峰，但没有Gr峰，这与Gr的含量有关(体积分数为1％)，显微硬度的测试结果表明，水淬试样170℃时效4小时达到峰值。TEM的结果表明，此试样中，SiC与基体结合良好，并发现尺寸较大的第二相(尺寸在1μm～3μm之间)，由于尺寸较大，且在原始样中发现，可能是在材料制备过程中形成的。 然后，在多功能内耗仪和DMA上对各热处理态试样的阻尼性能进行了全面测试，获得了内耗频率谱、温度谱和振幅效应谱。结果表明，五种热处理状态试样，低于100℃，阻尼性能几乎不受热处理制度的影响。在100℃～270℃范围内，不同热处理态材料阻尼能力的大小以次为：其炉冷＞空冷＞－70℃淬火≈-195℃淬火＞水淬。超过270℃，由于阻尼性能测试出现第二个内耗峰，不同热处理态试样阻尼性能的大小没有明显的规律性。当温度大于310℃，-195℃淬火与水淬试样表现出较高的阻尼性能。水淬试样在190℃的时效温度下有最高的阻尼性能，通过与炉冷试样的阻尼性能(五种热处理制度炉冷试样的阻尼性能较高)对比发现，在温度低于120℃、高于290℃范围，水淬试样在190℃时效温度下的阻尼性能均高于炉冷试样的阻尼性能，在120℃～290℃之间，它的阻尼性能低于炉冷试样的阻尼性能，而此温度区间正好是位错内耗峰出现的温度范围。在温度低于120℃，水淬试样的内耗值几乎不变，保持在0.004(tanφ值)以上，而炉冷试样仅在75℃以下保持在0.0015左右，前者的内耗值为后者的两倍以上。这一结果很有意义，因为此复合材料作为结构件使用时，常采用固溶处理工艺提高其力学性能，但炉冷试样却有着较好的阻尼性能(主要在位错阻尼机制发挥作用的温度范围，低温段阻尼性能相近，这是材料使用上面临的一个矛盾，热处理工艺对低温段阻尼没有影响)，不同时效温度的研究为这一问题提供了一个思路，进一步研究这一机制，有望获得高的常温阻尼，对材料的使用有很大的意义。 从0.1Hz～10Hz此材料内耗值随频率的升高而下降，随后内耗随频率的升高而上升，但30Hz的阻尼性能仍低于O.1Hz的阻尼性能。另外，此材料的内耗有郑州大学硕士学位论文摘要应变相关性，内耗随应变振幅线性增加。 各种热处理状态试样，在150℃一260℃范围内均出现温度内耗峰几，峰。分析表明，此峰为位错峰，因为该峰从峰的位置，频率驰豫特性，以及阻尼性能测量的应变振幅相关性，都与G一L理论符合的很好。炉冷、空冷、干冰冷和液氮冷四种热处理制度根据几，峰峰温数据计算的激活能的结果约为1·seV，接近于铝的自扩散激活能1.45eV。而水淬试样在不同的时效温度下激活能计算的结果有很大的不同，激活能最低为1.27eV，最高为2.4leV。 除炉冷试样外，其余各热处理态试样均在300℃左右，有一内耗峰几2峰，此内耗峰无驰豫特性。频率变化，内耗峰的位置不变，对同一热处理态试样内耗峰位置不变。几2峰峰的位置温度大小依次为:空冷试样<水淬试样<干冰冷试样<液氮冷试样。对于水淬试样在不同的时效温度下，几2峰峰的位置温度大小依次为:210℃时效<170℃时效<120℃时效<150℃时效<190℃时效，有凡2峰的这些特点可知，几2峰不是晶界内耗峰，晶界内耗峰有弛豫特性，属于相变峰，炉冷试样没有此内耗峰，说明此峰与溶质原子在晶粒内的分布有关，且冷速提高，此峰的位置向高温移动，由于此峰的峰位在300℃左右，时效并不能消除此峰，由于相变往往与力学性能的突变相联系，所以，有必要做力学性能的试验，搞清楚其对力学性能的影响，同时，在606lAUsiCp复合材料的阻尼试验中没有发现此峰，说明此峰可能与合金元素的含量有关。总之，目前的试验结果不足以弄清楚此峰的具体机理，需做进一步研究。 总的来说，低温下，此材料中占优势的阻尼机制为位错阻尼、界面阻尼以及材料的固有阻尼，在较高的温度，位错、界面滑动及晶界阻尼共同起作用。更多还原

【Abstract】 In this paper, 6013Al/SiCp/Gr Metal Matrix Composite (MMC) was produced by spray codeposition, By means of changing the medium of quenching, influence of five types of heat treatment system(furnace cooling, air cooling, water quenching, dry ice quenching, liquid nitrogen quenching)and different aging temperature on the damping was studied systematically. Furthermore, relaxation damping peaks appearing in every heat treated sample were analyzed.First of all, every heat treated sample were analyzed by using optical microscope (OM). Sequently X radio diffraction(XRD) was used to study the original sample . We also studied the microhardness of the sample which were quenched in water and aged at different temperature .Further more, the original sample was analyzed by using transmission electricity microscope(TEM). The results show that SiC particulate distributes equably in the matrix, and that the peak of SiC can be gotten in the XRD spectrum but the peak of Gr can’t (volume friction is 1%). The testing of microhardness show that water quenching reach peak value aging about four hours. The TEM micrographs of the original sample show that SiC particulates generally exhibit a good contact at the particulates/matrix interfaces and a great deal of second phases disperse in the grain. It is likely to come from the process of producing the material because of its size(from lum to Sum).Drawing on a multifunctional internal friction instrument and DMA, we tested the damping capacity of all the heat treated samples completely, and then got the damping-frequency spectrum, temperature spectrum and strain amplitude spectrum . As the results manifest, damping capacity of different heat treated samples changes slightly at low temperature but remarkably at elevated temperature. Over a 100℃ to 270℃ temperature range, the damping capacities are ranked from great to small as follows: sample cooled in furnace, sample cooled in the air, sample quenched at -70℃ ( sample quenched at -195 )and sample quenched in water. The damping capacities don’t show some laws between 270℃ and 310℃ . Over 310℃ , liquid nitrogen quenching and water quenching show higher damping capacities . At the same time , water quenching at 190 ℃ aging exhibit the highest damping capacities. Compared with furnace cooling which show the highest damping capacities in five heat treatments , it show higher damping capacities when temperature is under 120℃ and above 290 ℃ . Further more, it show constantly damping value (tan above 0.004), but the damping value of furnace cooling is just 0.0015℃ under 75 ℃. This resultABSTRACTis important because the five heat treatment can’t have a different damping capacities at low temperature. If we study its mechanism, we have a hope of getting high damping capacities at low temperature.From 0.1 Hz to10Hz, the damping capacity of the material increase with frequency increasing. But the damping capacity at 30Hz is still lower than it at 0.1 Hz. Furthermore, the damping capacity of the material is relative of the strain and it increase linearly with strain increasing.All the heat treated samples have a damping peak over the range of 150℃ and 260℃ (called Tp peak).By analyzing , the peak is a dislocation peak and it can be explained with G-L theory. The activation energy of the Tpl peak is calculated being about 1.5 eV for four heat treated samples(furnace cooling, air cooling, dry ice quenching, liquid nitrogen quenching),and it is near the self diffuse activation energy of aluminum 1 .45eV. But the activation energy of water quenching samples are very different at different aging temperature, the lowest is 1.27eV and the highest is 2.4 leV.But for the furnace cooling samples , all samples have another damping peak about at 3 00℃ (called Tp2 peak) .The peak is not of relaxation model, the peaktemperature does not vary with frequencies. Furthermore, for a sample there is only one temperature. The peak temperature of Tp2 peak is ranked from small to greatas follows: sample cooled in更多还原