Ti3AlC2颗粒含量对Ti3AlC2/ZA27 复合材料性能的影响

Effect of Ti3AlC2 content on mechanical properties of Ti3AlC2/ZA27 composites

摘要:

通过无压烧结技术和机械合金化技术，在烧结温度为870 °C，保温时间为2.5h的工艺条件下，制备了四种不同体积含量的Ti3AlC2 颗粒含量的Ti3AlC2/ZA27复合材料。研究了Ti3AlC2 颗粒含量对Ti3AlC2 /ZA27复合材料的硬度，密度，拉伸强度和弯曲强度的影响。结果表明界面处的微弱的化学反应有助于提高复合材料的界面结合能力，进而提高Ti3AlC2 /ZA27复合材料的机械性能。此外，随着Ti3AlC2 颗粒含量增多，Ti3AlC2 /ZA27复合材料的硬度和力学强度都随之增大，这主要归因于纳米尺度的Ti3AlC2颗粒的弥散增强结果。然而，随着Ti3AlC2 颗粒的增加到40 vol. %, 由于孔隙的增多，Ti3AlC2 /ZA27复合材料的硬度和力学强度又出现下降。对比制得的四种Ti3AlC2 /ZA27复合材料，30Ti3AlC2/ZA27复合材料拥有最大的抗拉强度、抗弯曲强度以及维氏硬度，分别为310 MPa，528 MPa 和1.24 GPa. 这些优异的性能除了归因于良好的界面结合，还归因于Ti3AlC2颗粒的细晶强化和弥散强化作用。

Abstract:

ZA27 alloy-based composites reinforced by 10–40 vol. % Ti3AlC2 particles in a step of 10 vol. % were prepared by pressurelessly sintering mechanical alloyed powders at 870 °C for 2.5 h. The effects of Ti3AlC2 content on hardness, density, stretching and bending performance were studied. The results demonstrate that a well bonded interface could be obtained by weak reaction occurred at the interface between Ti3AlC2 and ZA27 alloy during sintering process, and which is beneficial to the mechanical properties of the Ti3AlC2 /ZA27 composites. An increase in Ti3AlC2 content (up to 30 vol. %) leads to enhanced hardness and mechanical strength of the composites due to dispersion strengthening of nano-sized Ti3AlC2 particle. However, with an increase in Ti3AlC2 content to 40 vol. %, the hardness and strength decrease because of the growing number of pores. Comparing the four composites with different Ti3AlC2 contents, the 30Ti3AlC2 /ZA27 composite possesses the best properties of 310 MPa for tensile strength, 528 MPa for bending strength and 1.24 GPa for Vickers hardness. Besides the good interfacial bonding, the improved mechanical properties of the Ti3AlC2 /ZA27 composites are also attributed to the fine-grained microstructure and well dispersed reinforcements.