Spray forming

About: Spray forming is a research topic. Over the lifetime, 1153 publications have been published within this topic receiving 12869 citations. The topic is also known as: spray casting & spray deposition.

Effect of (Mn + Cr) addition on the microstructure and thermal stability of spray-formed hypereutectic Al–Si alloys

Abstract: Microstructures and thermal stability of hypereutectic Al–Si alloys with or without (Mn + Cr) addition, prepared via Spray Forming technique, are studied and compared with traditional cast alloys with same composition, using scanning electron microscopy with energy diffraction spectrum, X-ray diffraction, transmission electron microscopy and differential scanning calorimeter. The results show that the Fe-bearing and primary silicon phases in SF-3C alloy can be refined to less than 10 μm, especially in SF-MC21 alloy the Fe-bearing phase is refined into uniformly distributed α-Al(Fe,Mn,Cr)Si phase particles with sizes smaller than 5–6 μm, contributing to the decrease/elimination of the deleterious effect of needle-like Fe-bearing phases. The results of different heat treatments show SF-MC21 alloy possesses excellent thermal stability than SF-3C alloy which is unstable below 750 K for the coarsening of β-Al5FeSi phase and formation of Al7Cu2Fe phase. The study indicates that both the existence of thermodynamically stable α-Al(Fe,Mn,Cr)Si particles and the increase of solidus temperature of SF-3C alloy induced by adding (2Mn + 1Cr) elements contribute to the high thermal stability of SF-MC21 alloy. Contemporarily, combined the phase reactions or transformation occurred during the melting and solidification processes of both spray-formed hypereutectic Al–Si alloys, the microstructure formation of spray-formed alloys is discussed.

Carbon nanotube reinforced aluminum nanocomposite via plasma and high velocity oxy-fuel spray forming.

Abstract: Free standing structures of hypereutectic aluminum-23 wt% silicon nanocomposite with multiwalled carbon nanotubes (MWCNT) reinforcement have been successfully fabricated by two different thermal spraying technique viz Plasma Spray Forming (PSF) and High Velocity Oxy-Fuel (HVOF) Spray Forming. Comparative microstructural and mechanical property evaluation of the two thermally spray formed nanocomposites has been carried out. Presence of nanosized grains in the Al-Si alloy matrix and physically intact and undamaged carbon nanotubes were observed in both the nanocomposites. Excellent interfacial bonding between Al alloy matrix and MWCNT was observed. The elastic modulus and hardness of HVOF sprayed nanocomposite is found to be higher than PSF sprayed composites.

Microstructure and mechanical properties of spray deposited hypoeutectic Al-Si alloy

Abstract: The microstructure and the tensile properties of an Al–8.9 wt.% Si–3.2 wt.% Cu–0.9 wt.% Fe–0.8% Zn alloy processed by spray forming was investigated. The alloy was gas atomized with argon and deposited onto a copper substrate. The microstructure was evaluated by optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Small faceted dispersoids observed surrounding equiaxial α-Al matrix were identified by SEM–EDS as silicon particles. Sand cast samples with the same composition showed a columnar dendritic α-Al matrix, Al–Si eutectic, polyhedric α-AlFeSi and needle-like β-AlFeSi intermetallics. In the spray formed material the formation of the Al–Si eutetic was suppressed, and the formation of the α-AlFeSi and β-AlFeSi intermetallics was strongly reduced. The fine and homogeneous microstructure showed an aluminium matrix with grain size ranging from 30 to 40 μm, and particle size of the silicon dispersoids having a mean size of 12 μm. Room temperature tensile tests of the spray formed alloy showed relative increasing of strength and elongation when compared with the values observed for the conventionally cast counterparts. These results can be ascribed to the refined microstructure and the scarce presence of intermetallics of the spray formed material.

Hot-deformation behaviour of spray-formed 2014 Al + SiCP metal matrix composites

Abstract: In the present investigation, discontinuous SiC particle reinforced 2014 Al alloy based metal matrix composites have been produced by spray forming process. The composites contained average particle sizes of 17, 30 and 58 μm in the range of 5–11 vol.%. The composites were tested for their compressive flow behaviour, in unlubricated condition, at strain rates of 0.01, 0.1 and 1.0 s−1 and at temperatures of 150, 300 and 450 °C. The flow stress for 30 μm size particle reinforced composite increased with increasing particle content from 0 to 8.5 vol.%, but decreased at 11 vol.%. The flow stress invariably decreased at larger strain values during deformation. The increase in particle size from 17 to 30 μm led to increase in flow stress at 300 °C, whereas, it decreased at 450 °C. The strain rate sensitivity (m) for 30 μm size particle reinforced composite was close to 0.16 up to 8.5 vol.%, whereas, for the composite with 17 μm size particles it decreased to 0.13 with increasing volume fraction up to 8.6 vol.%. The m values increased from 0.13 to 0.15 with increase in particle size from 17 to 58 μm. The variation in flow behaviour has been attributed mainly to particle fracture and debonding at particle/matrix interface, confirmed by microstructural features of the deformed samples. The major particle fracture events were recorded at low temperature and low strain rate of deformation. The composite with 30 μm size particles showed enhanced restoration process based on the low value of calculated apparent activation energy for diffusion (80–100 kJ mol−1). This deformation behaviour of the composites has been discussed in light of microstructural observations and the void formation during deformation.