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.

Precision spray forming - layer-by-layer rolling repair and manufacturing equipment

Abstract: The utility model provides precision spray forming-layer-by-layer rolling repair and manufacturing equipment, which comprises the following mechanisms or functional components: an injection unit and a layer-by-layer rolling repair and manufacturing unit. The injection unit comprises a liquid metal smelting preparation or supply device used for providing liquid metal and an inert gas atomization and injection device arranged at the downstream of the liquid metal smelting preparation or supply device; and the layer-by-layer rolling repair and manufacturing unit comprises a heating device which is arranged at the periphery of the work piece to be coated and preheats the surface of the work piece to be coated, a layer-by-layer rolling device which is arranged at one side of the metal coating and is used for rolling the metal coating layer by layer, a movable mechanical operating device which is used for holding the work piece to be coated, and a metal coating thickness detection and control mechanism which is connected with the layer-by-layer rolling device.

Hot deformation behavior and microstructure evolution of the spray deposited and secondary hot extruded 2195 Al-Li alloy

Abstract: This work aims to investigate the influence of hot deformation parameters on the microstructure evolution and deformation behavior of the extruded 2195 Al–Li alloy, as well as to explore its optimized hot deformation windows based on the hot compression tests carried out on a Gleeble-1500 thermo-mechanical simulator in the temperature range 370–520 °C and with the strain rate of 0.001–10 s −1 . The results revealed that the extruded 2195 Al–Li alloy plate with a large aspect ratio had a lower deformation activation energy with respect to the spray deposited and as-cast 2195 Al–Li alloys owing to the existence of a large number of coarse second phases and LAGBs in the extruded plate. The optimized hot deformation temperature of the alloy ranged from 405 °C to 490 °C with a strain rate from 0.001 to 0.1 s −1 . Hot deformation under the optimized conditions led to the occurrence of continuous dynamic recrystallization and resultant microstructure refinement. Although the occurrence of continuous dynamic recrystallization weakened the <101> deformation texture, but triggered another texture component with <001>//ND. Deformation at low temperature and high strain rate induced flow instability due to insufficient dynamic softening. In addition, the flow instability at a temperature higher than 490 °C arose from partial remelting of Al 2 Cu phase along grain boundaries. The work can provide an effective guidance for the designation of secondary hot processing of the extruded 2195 Al–Li alloy.

Modeling of droplet dynamic and thermal behaviour during spray deposition

Abstract: Mathematical modeling of supersonic gas atomization for spray forming has been investigated. Influence of the droplet dynamic and thermal behaviour on the resultant microstructure has been studied. Analytical models have been constructed taking into account the higher Reynolds number owing to supersonic gas flow. The impact velocity profiles of the droplets lend credence to the evolution of equiaxed grain morphology through dendrite fragmentation. The thermal history profile along with the fraction solid plot could yield optimized standoff distance to obtain a mushy droplet. A comparison of secondary dendrite arm spacing obtained from the mathematical model showed good agreement with experimental observations.

Spray Forming and Post Processing of Superalloy Rings

Abstract: Spray forming as a technology to produce near net shape components or preforms for additional forming operations with defined microstructural properties is well known for several alloys and applications. The production of spray formed superalloy rings made of IN718 and U720 for aero engine components in order to reduce production cost is the goal of the current EU-research project. Several spray runs were carried out at University of Bremen to optimize the process parameters regarding a low porosity, low segregation and a high yield. Macro and microetchings were prepared to analyze the influence of the parameter variations on before mentioned structural properties. Several optimized rings were used to examine the influence of thermomechanical processing on porosity and microstructure of spray formed superalloy rings. Hot isostatic pressing and forging processes were performed separately as well as in combination in order to obtain the ideal post processing route, which was determined via microstructure analysis. As a result of this project, it became clear that HIPping is an integral part of the postprocessing of as-sprayed material, due to the fact that it was not possible to produce as-sprayed material without porosity. The development of micro- and macro structural properties through all these processes and their variations will be shown. Another paper presented here will focus on the final properties and applications of this material.