Mo对TiC/Al复合材料组织和性能的影响

为了细化TiC/Al基复合材料中的增强颗粒,进一步提高TiC颗粒对基体的强化效果,在锻铝6A02基体中加入适量Mo元素,用原位合成的方法制备TiC/Al基复合材料.对制备得到的铸态和轧制态材料进行了显微组织观察、拉伸和磨损实验.结果表明,TiC颗粒可以作为异质形核核心起到细化基体组织的作用.TiC颗粒的引入提高了材料在室温和高温的抗拉强度和屈服强度,同时改善了材料的耐磨损性能,且随着载荷的增加,耐磨性能的提高越明显.当加入质量分数1.0%的Mo时,可改善基体对TiC颗粒的润湿性,细化TiC颗粒的尺寸(0.5μm),使TiC颗粒分布更为均匀,材料的力学性能和磨损性能得到提高.然而,过高的Mo含量将导致在组织中出现粗大的脆性Al5Mo相,同时使材料的力学性能和磨损性能有所降低.

Effects of Mo on microstructure and properties of TiC/Al composites

In order to improve the reinforcement of TiC on Al matrix material,the element of Mo had been add into the 6A02 (LD2) aluminum based alloy to reduce the size of in situ TiC particulates. Microstructure of ascast piece and rolled piece had been observed,and tensile properties and wear properties had been tested. The results show that TiC particulates can act as heterogeneous nucleation sites,which results in refined microstructure. Either at room temperature or at high temperature,the ultimate tensile strength (UTS) and yield strength of the composites increase with addition of TiC particulates. Wear resistance of the TiC reinforced composites is improved remarkably,especially when the contact load is developed. 1. 0wt% Mo additive to the alloy improves the wettability of Al melt on TiC particles. Moreover,the distribution of TiC particles in the base alloy becomes more uniform and the size of TiC is reduced to 0. 5 μm in diameter,which leads to the development of mechanical properties and wear resistance. However,the excess of Mo addition causes the brittle Al5Mo precipitate in the microstructure,and then the composites exhibit the worsening mechanical properties and wear property.