微觀組織及力學性能的影響
(1. 鄭州大學 物理工程學院，鄭州 450052；
2. 登封電廠集團鋁合金有限公司，登封 452477)
摘 要: 采用K2TiF6和KBF4混合鹽原位反應法制備TiB2/Al-7Si復合材料，利用XRD、SEM、金相顯微鏡、HV硬度測試和磨損實驗等方法研究了Mg對復合材料的微觀組織和力學性能的影響。結果表明：反應生成的TiB2顆粒平均尺寸約為0.5 μm，材料的硬度和耐磨性隨著TiB2含量的增加而提高；添加1.5%Mg(質量分數)元素可明顯細化TiB2顆粒，且使其分布更加均勻，增強TiB2顆粒的彌散強化和細晶強化效果，復合材料的硬度和耐磨性顯著改善；過量的Mg元素(3%)會造成TiB2顆粒細化效果的下降，但其硬度和耐磨性能繼續(xù)得到改善。
關鍵字: TiB2/Al-7Si復合材料；Mg；微觀組織；硬度；力學性能
in-situ TiB2/Al-7Si composite
YU Huan-wei1, REN Bo1, LIU Shuan-jiang1
（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
