Microstructures and mechanical properties of in-situ TiB2/Al−xSi−0.3Mg composites  

原位TiB2/Al−xSi−0.3Mg复合材料的显微组织与力学性能

作　　者：Yu-xuan LIU Ri-chu WANG Chao-qun PENG Zhi-yong CAI Zhao-hui ZHOU Xiao-geng LI Xuan-yang CAO 刘宇轩;王日初;彭超群;蔡志勇;周朝晖;李晓庚;曹玄扬(中南大学材料科学与工程学院,长沙410083;中南大学轻质高强结构材料国防科技重点实验室,长沙410083;长沙新材料产业研究院,长沙410000)

机构地区：[1]School of Materials Science and Engineering,Central South University,Changsha 410083,China [2]National Key Laboratory of Light High Strength Structural Materials,Central South University,Changsha 410083,China [3]Changsha Advanced Materials Industrial Research Institute,Changsha 410000,China

出　　处：《Transactions of Nonferrous Metals Society of China》2021年第2期331-344,共14页中国有色金属学报（英文版）

基　　金：The authors are grateful for the financial supports from the National Natural Science Foundation of China(51804349);the China Postdoctoral Science Foundation(2018M632986);the Natural Science Foundation of Hunan Province,China(2019JJ50766).

摘　　要：In-situ 2 vol.%TiB2 particle reinforced Al−xSi−0.3Mg(x=7,9,12,15 wt.%)composites were prepared by the salt−metal reaction,and the microstructures and mechanical properties were investigated.The results show that the TiB2 particles with a diameter of 20−80 nm and the eutectic Si with a length of 1−10μm are the main strengthening phases in the TiB2/Al−xSi−0.3Mg composites.The TiB2 particles promote grain refinement and modify the eutectic Si from needle-like to short-rod shape.However,the strengthening effect of TiB2 particles is weakened as the Si content exceeds the eutectic composition,which can be attributed to the formation of large and irregular primary Si.The axial tensile test results and fractography observations indicate that these composites show more brittle fracture characteristics than the corresponding alloy matrixes.采用盐−金属反应制备原位2%TiB2(体积分数)颗粒增强Al−xSi−0.3Mg(x=7%,9%,12%,15%,质量分数)复合材料,并对其显微组织和力学性能进行研究。结果表明,TiB2/Al−xSi−0.3Mg复合材料中的主要强化相是直径为20~80 nm的TiB2颗粒和长度为1~10μm的共晶硅相。TiB2颗粒能促进晶粒细化,使共晶硅由针状变为短棒状。但是,当Si含量超过共晶成分时,TiB2颗粒的强化作用减弱,这可能是由于形成了大且不规则的初生Si相。轴向拉伸试验和断裂观察结果表明,复合材料比相同成分的基体合金具有更多的脆性断裂特征。

关 键 词：Al−Si alloy in-situ reaction aluminum matrix composite microstructure mechanical properties 

分 类 号：TB33[一般工业技术—材料科学与工程]