Study On In-Situ Synthesis And Microstructure Of TiC In Al Melt Based On Reactive Wetting

Particle reinforced Al matrix composites have been widely used in many fields due to their high specific strength and hardness,good thermal conductivity,and thermal stability.The aggregation of reinforcing particles affects the properties of composites.It is found that carbon source can be introduced into Al melt and in-situ synthesis TiC by reactive wetting,and the microstructure distribution can be improved by adjusting the reactivity between Ti-C,so the properties of the composites can be effectively improved.In this paper,TiC particles reinforced Al matrix composites were prepared by melting reaction method with Ti powder,Graphite,Diamond and SiC as raw materials.The XRD,SEM,and EDS testing methods were conducted to analyze the microstructure and composition analysis.The influence of different factors on the microstructure of in-situ TiC reinforced Al matrix composites and the reaction process in different systems were investigated.The main conclusions are as follows:1.Based on Ti-C system,Graphite and Diamond were introduced into Al melt by reactive wetting,and TiC was in-situ synthesized.The effects of melt temperature and carbon source particle size on microstructure uniformity were studied.It is found that decreasing melt temperature and carbon source particle size were beneficial to improve the microstructure uniformity of TiC.For example,the microstructure uniformity of the composites prepared by 4?m Graphite is better than that of the composites prepared by30?m Graphite.The microstructure uniformity of the composites prepared by 6?m Diamond is better than that of the composites prepared by 10?m Diamond.2.Based on Ti-C-Si system,the synthesis and microstructure of TiC in Al melt were studied.It is found that the addition of Si to Ti-Graphite/Diamond system can promote the reaction between Ti-C,but the microstructure uniformity of synthesizing TiC becomes worse.It's easy to form large TiC clusters when Graphite is used as carbon source.When Diamond is used as carbon source,on the one hand,the distribution range of TiC size increases,and more than 10?m TiC particles would be formed.On the other hand,with the increase of Ti,it is easy to form Al@TiC core-shell particles.3.The feasibility of synthesis TiC in Al melt based on Ti-SiC system and using SiC as carbon source was studied.It is found that SiC can be introduced into Al melt by the reaction of Ti-SiC.When 20?m SiC as carbon source,the reaction of Ti-SiC is insufficient,and the SiC@Al₄C₃@TiC particles was formed.When 5?m SiC as carbon source,the reaction of Ti-SiC is improved,and the reaction product is mainly Al@TiC particles.