R.T. Li

Effects of Al-Cr-Fe Quasicrystal Content on Tribological Properties of Cold-Sprayed Titanium Composite Coatings

Titanium (Ti) composite coatings were prepared on commercially available Ti substrates via a cold-spray process. Quasicrystalline Al-Cr-Fe particles were incorporated in the cold-sprayed Ti matrices at different contents to form a new type of wear-resistant Ti composite coating. The tribological properties of the Ti composite coatings were systematically investigated using steel ball-on-disc microtribological testing. The incorporation of 10 wt% Al-Cr-Fe particles gave rise to the higher wear resistance of the Ti composite coating than that of the Ti coating due to the higher wear resistance of the Al-Cr-Fe particles than that of the Ti matrix. As a result, an increase in the Al-Cr-Fe particle content to 20 wt% increased the wear resistance of the Ti composite coating. However, the wear resistance of the Ti composite coating decreased with a further increase in the Al-Cr-Fe particle content to 30 wt% due to the significantly increased volume of micropores in the composite coating. It could be concluded that the Ti composite coating with 20 wt% Al-Cr-Fe particles had the highest wear resistance among the cold-sprayed coatings used in this study.

Mechanical and Tribological Properties of Spark Plasma–Sintered Titanium Composites Filled with Different Al-Cr-Fe Quasicrystal Contents

A new type of Ti composite filled with Al-Cr-Fe quasicrystals (QCs) was developed via a spark plasma sintering process. The mechanical and tribological properties of the Ti/QC composites were systematically investigated. It was found that the hardness of the Ti/QC composites significantly increased with increased QC content due to the higher hardness of incorporated QCs than that of the Ti matrix. The tribological results clearly showed that the wear of the Ti/QC composites apparently decreased with increased QC content to 20 wt% as a result of the increased wear resistance of the composites. An excessive loading of 30 wt% QCs resulted in the decreased wear resistance of the Ti/QC composites. It could be concluded that the incorporation of QCs significantly improved the mechanical and tribological properties of the Ti/QC composites with an optimized QC content of 20 wt%.

Novel Ti based metal matrix composites reinforced with Al–Cr–Fe quasicrystals approximants

Abstract In this work, Ti/Al–Cr–Fe metal matrix composites were fabricated with Ti as matrix and Al–Cr–Fe quasicrystal approximants as reinforcements using spark plasma sintering. In all samples a Ti3Al ring forms around each Al–Cr–Fe particle as a bonding layer between Ti and Al–Cr–Fe particles. In the sample sintered with a holding time of 5 min, there are only TiAl regions present at the Ti3Al/Al–Cr–Fe interface. However, in the samples sintered with a holding time of 10, 15 or 20 min, TiAl, Ti(Al,Cr)2 and L12 regions were detected at the Ti3Al/Al–Cr–Fe interface. The addition of Al–Cr–Fe particles into the Ti matrix was found to improve the mircrohardness to 460 HV and increase the wear resistance by more than 50%.