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.

Flow Stress Behavior of Al-Fe-V-Si Heat-Resistant Aluminum Alloy Prepared by Spray Forming under Hot-Compression Deformation

Abstract: The behavior of the flow stress of Al-Fe-V-Si heat-resistant aluminum alloy prepared by spray forming during hot compression deformation was studied. The results show that the true stress-true strain curves of the spray forming Al-Fe-V-Si heat-resistant alloy are characterized by a high true stress occurrence at the early stage of compression, followed by a steady flowing due to recovery and strain softening because of dynamic recrystallization. The flow stress of the alloy decreases with increasing deforming temperature and increases with increasing strain rate. The flow stress of the spray forming Al-Fe-V-Si heat-resistant aluminum alloy during hot compression deforming can be described by constitutive equation in hyperbolic sine function．The deformation activation energy of the alloy during hot deformation by Sellars-Tegart equation is much higher than those of the conventional aluminum alloy. The deformation activation energy decreases with decreasing strain rate at the beginning, then increases with decreasing strain rate. Keywords：Al-Fe-V-Si alloy；heat-resistant aluminum alloy；hot compression deformation；flow stress

Microstructural Characterization of Spray Formed FGH4095 Superalloy During Hot Deformation

Abstract: In order to study the hot workability and to optimize the processing parameters for spray formed FGH4095 superalloy, thermal compression tests for spray formed FGH4095 superalloy have been finished by using a Gleeble 1500 thermal simulated test machine at the strain rates of 0. 01—10. 0 s −1 and temperatures of 1050—1140 °C. The effects of strain rate and deformation temperature on the true stress-true strain curves and microstructure evolution were investigated. The results show that the generation of dynamic recrystallization (DRX) depends sensitively on deformation temperature. When the temperature was lower than 1080 °C, long and narrow necklace grains were shown in the microstructure. When the temperature increased to 1140 °C, new recrystallization grains were generated. The size and shape of γ′ precipitates in the grains have a very important effect as factors of hindering sufficient migration of dislocations on plastic deformation. The result of thermal processing map is in accord with the microstructure observation, and the best material thermal processing temperature is above 1128 °C.

HOT DEFORMATION BEHAVIOR AND MICROSTRUCTURAL STABILITY OF SPRAY FORMED Al-22Si-5Fe ALLOY

Abstract: Hot deformation behavior of spray forming Al-22Si-5Fe alloy at different deformation temperatures with isothermal constant strain rates of 0.005, 0.01, 0.03, and 0.05 s −1 was investigated by using Gleeble-1500 thermo-mechanical simulator, with maximum strain of 30%, the microstruc- tures were studied by using of OM and XRD method. The experimental results showed that the hot deformation behavior of spray formed alloy could also be described by a model containing Z parameter (Zener-Hollomon parameter). The calculated deformation activation energy of the studied alloy was consistent with the self-diffusion activation energy of Al atoms at lower deformation temperature, and much higher than the self-diffusion activation energy of Al atoms at higher temperature because of the influences of large content hard constitutes such as prime Si and Fe-bearing intermetallics. The Si particles changed little when deformed at low temperature, but coarsened obviously when deformed at elevated temperature of 698 K or above. The heating temperature had no obvious effect on the sizes of Fe-bearing intermetallics.

Al Effect on the Structure of the Spray Formed Fe88Si12 (at%) Alloy

Abstract: Fe-Si alloys have excellent soft magnetic properties, specially around 12 at% Si. However, its industrial application is limited because of the lack of ductility, which causes cracking during rolling operations for the fabrication of thin sheets. The reason of the brittleness of the high silicon alloys is a disorder/order reaction at low temperatures. The aim of this work is to analyze the effect of the addition of Aluminum on the crystalline structure of Fe-Si alloys. Samples with a chemical composition of Fe88Si12 and Fe87Si12Al1 (at%) were prepared by Spray Forming. The structure was studied by means of X-ray diffraction and Mossbauer Spectroscopy. The presence of the DO3 and α- Fe phases were observed

Solidification of aluminium spray-formed billets

Abstract: A critical part of the billet spray-forming process is the successive intermittent deposition of thin layers of semi-solid aluminium alloy at different points on the top surface of the billet. Each thin layer is made up of a large number of impacted semi-solid spray droplets. As successive layers of alloy are deposited significant re-melting and re-freezing of underlying layers can occur. If the layers become too dry, high porosity will result; if they are too wet, fluid dynamic surface instabilities are possible. In extreme cases no billet will form. The process is essentially incremental, so that heat fluxes within the deposit very close to the top surface play a major role in determining the final deposit microstructure.