[AlBO]_w/6061Al复合材料的时效硬化行为

Age hardening behavior of [AlBO]_w/6061Al composite

采用挤压铸造法制备了晶须体积分数为20%的硼酸铝晶须增强6061铝基([AlBO]w/6061Al)复合材料,并采用硬度分析、DSC示差热分析及透射电镜分析的方法对复合材料的时效行为进行了研究。结果表明,压铸法制备的Al18B4O33/6061Al复合材料中存在高密度的位错,同时复合材料基体晶粒细小。经固溶淬火处理后,随着时效时间的增加,复合材料的硬度值先下降而后又有所回升,并在8 h左右出现一个峰值硬度,其硬度明显高于6061Al合金。复合材料固溶处理后硬度值较高是由合金元素的固溶强化所致。由于Al18B4O33晶须和基体6061Al发生了严重的界面反应,使Mg元素大量消耗,导致峰时效强化效果不如固溶强化效果显著。

6061Al matrix composite reinforced by 20%（volume fraction） Al18 B4O33 whisker （[AlBO]w/6061Al） was fabricated by a squeeze casting technique. Age hardening behavior of the composite was investigated by means of hardness measurement, DSC and TEM. The results indicate that there are high density dislocations in the matrix of the composite and the grain of the matrix is finer compared with that of the 6061Al. It is also found that the hardness of the composite is much higher than that of the 6061Al, and with increasing aging time after solution treatment, hardness of the composite decreases firstly and then increases until a peak hardness reaches at 8 h aging. The highest hardness of the composite in the solution state is due to the solution strengthening. The decreasing peak hardening effect of the composite compared with 6061Al is caused by the decrease in amount of Mg element, which is resulted from the interracial reaction between Al18B4O33 whisker and 6061Al.