Effects of Effective Dendrite Size on Tensile Deformation Behavior in Ti-Based Dendrite-Containing Amorphous Matrix Composites Modified from Ti-6Al-4V Alloy

Abstract

Five composite sheets having different thicknesses were fabricated by varying cooling rates after a vacuum arc melting of a Ti-based amorphous matrix composite fabricated by adding alloying elements of Ti, Zr, V, Ni, Al, and Be into a Ti-6Al-4V alloy. These composite sheets contained 72 to 75 vol. pct of dendrites sized by 9 to 27 lm, and showed excellent tensile properties of yield strength of 1.3 GPa and elongation up to 6.5 pct. According to the observation of tensile deformation behavior of the 3-mm-thick composite sheet, many deformation bands were formed inside dendrites in several directions, and deformation bands met crossly each other to form widely deformed areas. Since the wide and homogeneous deformation in this sheet beneficially worked for the tensile strength and elongation simultaneously, the optimum effective dendrite size (12.1 lm) and sheet thickness (3 mm) were determined for the Ti-based amorphous matrix composite. The finite element method (FEM) analysis based on real microstructures was also conducted to theoretically explain the enhanced elongation in terms of effective dendrite size. The shape and location of deformation bands estimated from the FEM simulations were well matched with the experimental observations.

Plasticity improvement for dendrite/metallic glass matrix composites by pre-deformation

“…The size of the dendritic arm can be controlled by the cooling rate during casting [27]. The dendrite's volume fractions in samples A, B, C, and D are all~46% by analyzing the contrast of the SEM image, and similar results have been observed by Jeon et al [28]. X-ray diffraction patterns of the composites (not shown here) indicate that the dendritic phase is a β-Ti solid solution with a body-centered cubic crystal structure.…”

The Corrosion Behavior of Ti-Based Metallic Glass Matrix Composites in the H2SO4 Solution

“…One can clearly see from Figure 4a-c that the sizes of dendrites in these differently sized composites are evidently different. Note that the size of dendrites actually increases with the rod size, even though the dendrites' volume fraction in all these samples is almost the same, with a value around 57% [20]. The similar situation has been verified in other MGMCs [20,21].…”

“…Note that the size of dendrites actually increases with the rod size, even though the dendrites' volume fraction in all these samples is almost the same, with a value around 57% [20]. The similar situation has been verified in other MGMCs [20,21]. The dendrite sizes, measured by Image-Pro software (6.0, Media Cybernetics Inc., Rockville, MD, USA), are around 0.7, 0.9, and 1.2 µm for Φ2, Φ3, and Φ6 mm rods, respectively.…”

Review on the Research and Development of Ti-Based Bulk Metallic Glasses

“…Therefore, it is more difficult to obtain tensile ductility for BMGs including Ti-based BMGs. Few Ti-based BMG matrix composites have exhibited tensile plasticity [154][155][156]. Developing Ti-based BMGs with tensile ductility is still a challenge.…”