Synthesis and characterization of multi-walled carbon nanotube-reinforced Ti–Mg alloy prepared by mechanical alloying and microwave sintering

Abstract

Titanium-magnesium (Ti–Mg) alloy is a widely accepted bimetallic material suitable for biomedical applications. However, reduced wear and corrosion resistance, low strength and hardness, and stress shielding effect limit their widespread applications. Reinforcing multi-walled carbon nanotubes (MWCNTs) possessing low density, high modulus, and improved mechanical properties overcome the shortcomings of Ti–Mg alloy. In the present work, nanostructured Ti–Mg alloy was synthesized at room temperature and simultaneously reinforced with MWCNTs. The high energetic ball milling process (HEBM) has been successfully utilized to mechanically alloy Ti with Mg at room temperature by decreasing the grain size to the nanoscale and reinforcing the alloy with MWCNTs. The synthesized nanostructured powder size was 25 nm. Characterization results have shown the emergence of new phases like Ti4C4 and Mg2C3 as a result of mechanical alloying (MA). The reinforced alloy powder was consolidated by cold compaction and followed by microwave sintering. The consolidated sample crystallite size attained was 72 nm and then characterized by Nanoindentation, XRD, and SEM. XRD results show intermetallic compounds Mg2C3 and TiC in bulk samples. SADP TEM confirmed the retention of Nano and partial amorphous structures in the consolidated samples. The nanoindentation test revealed the hardness and elastic modulus values 0.93 GPa and 28.12 GPa, respectively, equivalent to CpTi and its associated alloys. The results are prevalent in those alloys used in biomedical applications produced by conventional melting and casting techniques and can be a potential biomaterial.

Keywords

• Ti
• Mg
• MWCNTs
• Ball milling
• Mechanical alloying
• SEM