Cold-sprayed Coatings based on High Strength Aluminium Alloys Reinforced By Quasicrystalline Particles: Microstructure and Key Properties

Abstract

This study presents significant advantages of coldspraying in performance of coatings based on Al matrix reinforced by metastable nano-and submicrosized quasicrystalline particles as compared to those processed by thermal spraying and, in particular, by high velocity oxy-fuel (HVOF) spraying technique.Two kinds of feedstock powders with nominal compositions Al^J^C^ and Al94Fe2.5Cr2.5Ti1 were employed in spraying the coatings on cold rolled steel substrate. Microstructure and key mechanical characteristics of feedstock powders and coatings performed by coldspraying and HVOF process were studied and discussed.The main benefit of cold-spraying as opposed to HVOF spraying was that the composite quasicrystalline structure of initial feedstock powders is retained in the interior of flattened particles heavily deformed under impact in solid state. Strain hardening of coating and substrate is resulted from impact during cold-spraying.The results showed that unlike to HVOF sprayed coatings important advantage of cold-sprayed quasicrystalline coatings is referred to combination of increased hardness with ductility indicated by plasticity characteristic just about critical value δ Η « 0.9, which is quite enough for preventing brittle failure of material during particle impact onto substrate or previously deposited particles.

Structural performance of nanoquasicrystalline composites based on Al-Fe-Cr-alloy: Synthesis and key characteristics

“…As opposed to this, cold-spraying offers essential advantages in remaining quasicrystalline particles since adiabatic increase of temperature affects only particle/particle interface while dislocation density of α-Al solid solution increases up to 10 15 m/m 3 . Melt-spun alloy 0.4037 10 11 Atomized powder 0,4042 10 13 Extruded material 0.4043 / 0.4011 10 16 Cold-sprayed alloy 0.4045 10 15 This result is in good agreement with the data published previously [13]. One of the α-Al solid solution has lattice parameter a , which is almost the same as that for as-atomized feedstock powder.…”

“…In addition, cold-spray technique was used to consolidate quasicrystalline powder in form of thick coatings with thickness about 800 μm. In cold spraying experiments, velocity of air/particle jet was roughly about V=750 m/s while its temperature was as high as 400 °C [13].…”

“…Among the other processes, rapid solidification by melt spinning [7,10] and powder atomisation technique [6,8,11] are thought to be mostly effective for mass production of quasicrystalline semi-products. Presently, hot extrusion and cold spraying technique as alternative process are developed to consolidate quasicrystalline semi-products in bulk shaped composite material [4,6,[11][12][13].…”

Wetting Behavior and Functionality Restoration of Cold-Sprayed Aluminum-Quasicrystalline Composite Coatings

“…Evidently, this category can be considered as candidate material for the fabrication of hydrophobic surfaces. Although thermal spray processes like high-velocity oxygen fuel (HVOF) and plasma spraying have been successfully employed in the deposition of hard and brittle quasicrystalline powders, the phase change during the high-temperature deposition is a constant challenge ( Ref 51,52). Furthermore, using QCs as reinforcing components in composite structures is a preferred strategy for avoiding mechanical problems caused by the inherent brittleness of these particles.…”