高体分粉煤灰颗粒增强铝基复合材料制备及性能研究

发布时间：2018-10-31 14:42

【摘要】：本实验以7075铝合金为基体材料,采用挤压铸造法将铝合金熔体压入粉煤灰颗粒堆积体内,制得复合材料。研究了压力、浇注温度、粉煤灰的体积分数等参数对材料制备的影响;通过对复合材料及基体合金进行金相分析、环境扫描电子显微分析、密度分析、布氏硬度分析、摩擦磨损性能测试等研究,探讨压力、浇铸温度、粉煤灰颗粒的体积分数对粉煤灰颗粒增强铝基复合材料显微结构、物理性能的影响。研究了粉煤灰体积分数、粉煤灰尺寸范围大小、磨损时间对复合材料摩擦磨损性能的影响,同时对复合材料的摩擦表面组织形貌及磨屑形貌进行了初步的分析,从而对复合材料的摩擦磨损机理特征进行探讨。研究结果表明:(1)通过挤压铸造的方法可以制备出来高体积分数的粉煤灰颗粒增强铝基复合材料,一般压力越大晶粒越细,界面结合越好,但同时也会造成一定的缺陷,例如粉煤灰微珠破裂;(2)浇注温度越高,粉煤灰分布的越均匀,粉煤灰和金属联系的更加紧密,但同时由于温度过高也会产生气泡、缩孔等缺陷;(3)粉煤灰的加入改善了材料的磨损性能,使材料的摩擦系数增大,于此同时,摩擦系数稳定性得到提高。同时,随着复合材料部分粉煤灰的相对含量增加,复合材料的摩擦磨损性能得到提高,粉煤灰体积分数为20%时,其摩擦磨损性能最佳。(4)加入小尺寸范围(106-212μm)的粉煤灰颗粒的复合材料比加入大尺寸范围(0-400μm)的粉煤灰颗粒的复合材料摩擦磨损性能好;(5)10 min为复合材料的磨损临界时间点,当磨损时间超过10 min后,磨损率增长幅度变大,磨损加快;(6)在摩擦磨损过程中,从复合材料中脱落下来的粉煤灰颗粒保留在两对磨面之间可以起到类似“滚珠”的作用,形成“三体”磨损,继而起到了减少磨损的作用(轴承效应)。
[Abstract]:In this experiment, 7075 aluminum alloy was used as the matrix material, the aluminum alloy melt was pressed into the fly ash particle accumulator by squeeze casting method, and the composite material was prepared. The effects of pressure, pouring temperature and volume fraction of fly ash on the preparation of the material were studied. By means of metallographic analysis, environmental scanning electron microscopy, density analysis, Brinell hardness analysis and friction and wear test, the pressure and casting temperature were discussed. Effect of volume fraction of fly ash particles on microstructure and physical properties of aluminum matrix composites reinforced by fly ash particles. The effects of volume fraction of fly ash, size range of fly ash and wear time on the friction and wear properties of composites were studied. Thus, the friction and wear mechanism of the composite is discussed. The results show that: (1) the high volume fraction fly ash particle reinforced aluminum matrix composites can be prepared by squeeze casting. The higher the pressure, the finer the grain size, the better the interfacial bonding, but at the same time, some defects will be caused. For example, fly ash microbeads rupture; (2) the higher the pouring temperature, the more uniform the distribution of fly ash, and the closer the relation between fly ash and metal. (3) the addition of fly ash improves the wear performance of the material, increases the friction coefficient of the material, and at the same time, the stability of the friction coefficient is improved. At the same time, with the increase of the relative content of fly ash, the friction and wear properties of the composite are improved, when the volume fraction of fly ash is 20, The friction and wear properties of the composites are the best. (4) the friction and wear properties of the composites with small size fly ash particles (106-212 渭 m) are better than those with large size fly ash particles (0-400 渭 m). (5) 10 min is the critical wear time point of the composites. When the wear time exceeds 10 min, the wear rate increases greatly and the wear rate accelerates. (6) in the process of friction and wear, the particles of fly ash falling off from the composite material can play a similar role to "ball" between the two pairs of abrasive surfaces and form "three-body" wear. In turn, it has the effect of reducing wear (bearing effect).
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB333

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