Influence of carbon reinforcements on the mechanical properties of Ti composites via powder metallurgy and hot extrusion

摘要

Ti metal matrix composites (Ti-MMCs) reinforced by vapor grown carbon nanofiber (VGCF) and graphite particle (Gr) were prepared via powder metallurgy and hot extrusion. Ti with 0～0.4wt% VGCF/Gr mixture powders were consolidated by using spark plasma sintering (SPS) at 800 ℃. Hot extrusion was then performed at 1000 ℃ with an extrusion ratio of 37:1. Microstructures and mechanical properties of the as-extruded Ti composites were investigated. Tensile strength of Ti-VGCF/Gr composites was steadily augmented when additions of VGCF/Gr were increased from 0.1 to 0.4 wt%. YS and UTS were increased 40.2% and 11.4% for Ti-0.4wt%VGCF as compared to pure Ti, while those values were 30.5% and 2.1% for Ti-0.4wt%Gr. The strengthening mechanism including grain refinement, carbon solid solution strengthening and dispersion hardening of TiC/carbon was discussed in detail.