Study of Al–Cu–Fe–Ti–Cr–Si powders for thermal spraying produced by mechanochemical synthesis and subsequent annealing

Abstract

The paper examines the phase transformations of composite powders based on Al 63 Cu 25 Fe 12 that contain alloying elements (Ti, Cr, Si in the ratio AlCuFe : TiCrSi = 75 : 25). The powders are produced by mechanochemical synthesis and subsequent thermal treatment. Amorphous and crystalline powder mixtures form during synthesis; their annealing results in multiphase structures consisting of α, β 1 , and β 2 phases. High-temperature x-ray diffraction has revealed an α-phase between 700 and 900°C. The new α-phase should be regarded as a 1/1 approximant of the nonequilibrium quasicrystalline phase. The maximum content of the approximant phase (68 wt.%) is observed after five-hour synthesis and subsequent annealing (T = 700°C, τ = 2 h) of pressed powders, microhardness of the particles reaching 8900 MPa.