微观组织及力学性能的影响
(1. 郑州大学 物理工程学院，郑州 450052；
2. 登封电厂集团铝合金有限公司，登封 452477)
摘 要: 采用K2TiF6和KBF4混合盐原位反应法制备TiB2/Al-7Si复合材料，利用XRD、SEM、金相显微镜、HV硬度测试和磨损实验等方法研究了Mg对复合材料的微观组织和力学性能的影响。结果表明：反应生成的TiB2颗粒平均尺寸约为0.5 μm，材料的硬度和耐磨性随着TiB2含量的增加而提高；添加1.5%Mg(质量分数)元素可明显细化TiB2颗粒，且使其分布更加均匀，增强TiB2颗粒的弥散强化和细晶强化效果，复合材料的硬度和耐磨性显著改善；过量的Mg元素(3%)会造成TiB2颗粒细化效果的下降，但其硬度和耐磨性能继续得到改善。
关键字: TiB2/Al-7Si复合材料；Mg；微观组织；硬度；力学性能
in-situ TiB2/Al-7Si composite
（1. College of Physics Engineering, Zhengzhou University, Zhengzhou 450052, China;
2. Deng Dian Ji Tuan Aluminum alloys Co. Ltd., Dengfeng 452477, China）
Abstract:In-situ TiB2/Al-7Si composites were fabricated by K2TiF6 and KBF4 compounds reaction in Al-7Si melt. The effect of Mg on the microstructures and mechanical properties of TiB2/Al-7Si were investigated by using XRD, SEM, optical microscopy, hardness and wear testing techniques. The results show that TiB2 particles with average size of about 0.5 μm are produced. The hardness and wear resistance increase with increasing TiB2 content. Adding about 1.5%Mg in melt restrains the conglobation of the TiB2 particles, which makes the size of TiB2 particle decrease and the distribution of TiB2 particle is more homogeneous. The strengthening effect of TiB2 particles is enhanced and the hardness and wear resistance of composites are obviously improved. The excess Mg decreases the refinement effect of TiB2 particles, but the hardness and wear resistance are improved continuously.
Key words: TiB2/Al-7Si composites; Mg; microstructure; hardness; mechanical properties
