原位合成TiC/Al(7075)复合材料的组织及力学性能

摘要

TiC/Al(7075) composites were fabricated by in situ reaction.The influence of in situ TiC particles form,distribution state and content on the microstructure and mechanical properties of the TiC/Al(7075) compo-sites were discussed.The results show that most spherical in situ TiC particles with aggregate exists in 7075 matrix,the cluster of grain size is about 1 μm.When the mass fraction of in situ TiC particles is less than 6%,the TiC distribution is more uniform.With the increase of in situ TiC particles,the grain sizes of the TiC/Al(7075) composites decrease significantly.But the porosity appear in the microstrcuture when the mass fraction of in situ TiC particles is more than 6%.Hardness and toughness of composite material testing shows that with the increase of the TiC particle concentration,the highest hardness of the surface reaches HB 108,the composites with 6% TiC have the best toughness,the toughness increases by 31.55% compared with the 7075 matrix.%采用原位合成法制备TiC/Al(7075)复合材料,研究原位TiC颗粒的存在形式、分布状态及不同原位TiC颗粒含量对TiC/Al(7075)复合材料的微观组织及力学性能的影响.结果显示,TiC颗粒多以近球形团聚态存在于7075铝基体中,颗粒团大小约为1 μm.当原位TiC颗粒质量分数小于6%时,原位TiC颗粒分布较为均匀,随着颗粒含量的增加,TiC/Al(7075)复合材料的铸态组织由蔷薇状组织逐渐转变为等轴晶组织,晶粒尺寸也随着原位TiC颗粒含量的增加而减小.当原位TiC颗粒的质量分数大于6%时,组织中出现气孔.复合材料的硬度和抗冲击韧性测试表明,TiC/Al(7075)复合材料的硬度随TiC颗粒含量的增加而增加,最高硬度达HB 108,冲击韧性在颗粒质量分数为6%时达到最佳,较基体提升31.55%.