材料期刊网

LD2为了解AIN颗粒对不同强度等级的铝合金的增强效果及机制，对40％体积分数的AIN颗粒增强1070、1061、LY12铝合金复合材料拉伸前后的微观组织进行了观察，发现拉伸前在基体中存在由热错配引起的高密度位错，在AIN颗粒的内部也存在大量的位错，拉伸后基体中的位错增殖，同时，AIN颗粒中的位错亦增多．力学性能的测试结果表明，AIN颗粒对低强度、高塑性的β纯铝增强率最高，中等强度、较高塑性的LD2铝合金不仅有较高的增强率，而且保持了一定的塑性．AIN颗粒对基体的这种选择性主要与AIN颗粒在拉伸过程中产生微量变形，从而松弛部分界面应力有关．LY12基体的塑性较低，易产生低应力断裂，因此，AIN颗粒的增强作用难以得到充分发挥．

In order to investigate the strengthening effect and mechanism of AIN particles in aluminum alloyswith different strength levels the microstructure of AIN particles reinforced 1070, 6061 and 2024 aluminum al-loy based composites ( Vf = 40% ) were observed before and after tension. The high density of dislocationsgenerated by thermal misfit were found in both matrix and AIN particles before tension. After tension, the dis-locations in the matrix and AIN particles propagate at the same time. The results of mechanical properties showthat amony three composites fabricated with various aluminum alloys, the highest strengthening rate can be ob-tained in the 1070 pure aluminum with low strength and high plasticity, and high strength and plasticity can beobtained in the 6061 alloy with medium strength and relativly higher plasticity. This may be related to the factthat ALN particles yield some micro-deformation during tension and relax some internal stress near the inter-face. Due to the low plasticity, AINp/2024 composite tends to fracture at low stress and it is very difficult forAIN particles to exploit their strengthening effect.