TiC/Ti层状复合材料组织与力学性能研究

Microstructure and Mechanical Properties of TiC/Ti Composites with Laminated Structure

摘要:

为了平衡钛基复合材料(Titanium matrix composites, TMCs)的强度和延展性,本文通过电泳沉积将氧化石墨烯(Graphene oxides, GOs)沉积到Ti箔表面,然后进行放电等离子烧结(Spark plasma sintering, SPS)制备了具有层状结构的原位TiC/Ti复合材料,并对复合材料进行冷轧和退火处理从而进一步优化复合材料的综合力学性能。结果表明烧结过程中,Ti箔表面的GOs与Ti基体反应形成了原位TiC,从而形成了TiC/Ti层状复合材料,随着沉积时间的增加,分布在Ti层之间TiC的含量增加；复合材料经过冷轧和退火后,退火态材料的晶粒为等轴晶,且TiC仍然保持层状分布特征。沉积时间120 s时,烧结态材料的抗拉强度(Ultimate tensile strength, UTS)为555 MPa,伸长率(Elongation, δ)为15%；退火态材料的UTS为568 MPa,δ为27%,相比于烧结态材料,退火态材料达到了较好的强塑性匹配。此外,基于微观组织及断裂行为的分析对复合材料的强韧化机制进行了讨论。

Abstract:

In order to balance the strength and ductility of titanium matrix composites (TMCs), in-situ TiC/Ti composites with layered structures have been prepared by graphene oxides (GOs) electrophoretic deposition on pure Ti foils followed by spark plasma sintering (SPS) process. In order to further modifying the mechanical property, the sintered composites were subjected to cold rolling and annealing. The results show that GOs on the surface of Ti foil reacts with Ti matrix to form in situ TiC phases, thus forming TiC/Ti layered composites. With increasing deposition duration, the content of TiC distributed between Ti layers increases. After cold rolling and annealing, the grains of annealed composites are equiaxed, and the TiC still planarly distributed in the composites. The ultimate tensile strength (UTS) and the elongation (δ) of sintered material are 555 MPa and 15% respectively, while the UTS of annealed material is 568 MPa and the δ is 27%. Compared with sintered materials, annealed material achieves good strength-plasticity synergy. In addition, the strengthening and toughening mechanism of composites was discussed based on the analysis of microstructure and fracture behavior.