Effect of Textures on Tensile Properties of Extruded Ti64/VGCF Composite by Powder Metallurgy Route

Patchara Pripanapong, Shu-Feng Li, Junko Umeda, Katsuyoshi Kondoh
2016 Materials Science & Engineering   unpublished
Monolithic Ti-6Al-4V and Ti-6Al-4V composited with vapor grown carbon fibers (VGCFs) were fabricated by powder metallurgy (P/M) route in this research. Spark plasma sintering (SPS) subsequent by hot extrusion was applied in order to fabricate a full-density and high strength composite materials. A severe plastic deformation-Ti grains. Dynamic recrystallization was observed in a low deformation temperature region, which yield point of material was also observed in the stress-strain curve.
more » ... train curve. Furthermore, the addition of VGCFs encouraged the dynamic recrystallization during hot extrusion. Ti64+0.4 wt-% VGCFs shows the highest tensile strength of 1192 MPa at the end part of the extruded rod where the temperature of material was lower compared to the tip and middle part during extrusion. Additionally, the improvement in tensile strength was contributed by solid-solution strengthening of carbon element origi-Ti matrix. Introduction. Ti-6Al-4V alloy (Ti64) is the most well-known among Ti alloys, and used in many industries. High specific strength, good corrosion resistance and biocompatibility promoted a widely use of Ti and its alloys such as in aerospace and automobile industries, or medical devices and prosthesis [1, 2]. Many researchers studied the effect of hot working on microstructure and mechanical properties of wrought or cast Ti64. A. Momeni et al. studied the effect of deformation temperature and strain rate on microstructure and flow stress of wrought Ti64 under hot compression test [3]. Ti64 specimens, which experienced a hot compression test at 1273 and 1323-grain with low flow stress on the microstructure. This correlated with the results proposed by T. Seshacharyulu et al. and R. Ding et al. for the cast Ti64 [4, 5]. G.Z. Quan et al. studied the modelling for dynamic recrystallization in Ti-6Al-4Al by hot compression test. The result shows that a flow stress decreases with the increasing of deformation temperature. The high deformation temperature promotes the mobility at the boundaries for annihilation of dislocation, and the nucleation and growth of dynamic recrystallization [6]. H.Z. Niu et al. studied the phase transformation and dynamic recrystallization (DRX) behaviour of Ti-45Al-4Nb-2Mo-B (at-%) alloy. The results show that the DRX modes were strongly depends on deformation temperature, and a decomposition of lamellar structure along