Al-Cr-Fe quasicrystals as novel reinforcements in Ti based composites consolidated using high pressure spark plasma sintering

Ti based metal matrix composites (MMCs) reinforced with Al-Cr-Fe quasicrystals have been prepared using high pressure spark plasma sintering (HP-SPS) with a high heating/cooling rate of 200 degrees C/min between 550 degrees C and 750 degrees C and without any isothermal process. As the sintering pressure increases, the compositional variation of Al-Cr-Fe reinforcements diminishes. It is found that under a sintering pressure of 250 MPa, the phases in Al-Cr-Fe powders, including two quasicrystals, decagonal Al-Cr-Fe and icosahedral Al-Cr-Fe, and two of their approximants, Al-9(Cr, Fe)(4) and Al-8(Cr, Fe)(5), can be preserved. An interfacial layer forms between Ti matrix and Al-Cr-Fe reinforcements in the sintering process. This interfacial layer consists of Al3Ti and AlTi. The incorporation of 20 wt.% Al-Cr-Fe particles into Timatrix was found to improve the microhardness to Hv 480 and reduce the wear rate by around 70%. This implies that Al-Cr-Fe is a promising reinforcement candidate for Ti. (C) 2016 Elsevier Ltd. All rights reserved.