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.

Spray-formed high-strength superalloys

Abstract: Five commercial nickel-base super-alloys, Rene’95, AF115, AF2-lDA, Astroloy, and MERL 76, were spray-formed into disk preforms. Metallurgical evaluation and hightemperature deformation studies were performed on the as-sprayed materials. Spray forming offers these super-alloys the advantages of rapid solidification: segregation-free, uniform structure with a fine grain size. The preforms demonstrated good forgeability even without superplasticity in the as-sprayed condition. All alloys were press-forged and supersolvusannealed. High-temperature strengths and stress rupture properties were compared, and AF115 shows the best temperature capability.

High-strength and high-ductility al alloy and process for production of the same

Abstract: An object of the present invention is to provide an Al—Zn—Mg—Cu 7000-series Al alloy having high ductility as well as having high strength. For attaining this purpose, an Al alloy having a structure in which an inclusion is not included is produced by reducing an amount of oxygen contained in an Al alloy that is obtained by solidifying a preform resulting from rapid solidification by preferably spray forming a molten metal of an Al—Zn—Mg—Cu 7000-series Al alloy with an inert gas. This Al alloy has, as mechanical properties at an ordinary temperature, a tensile strength of 600 MPa or more, and an elongation of 15% or more when the tensile strength is from 600 MPa or more and less than 800 MPa or an elongation of 10% or more when the tensile strength is 800 MPa or more, and is excellent in cold workability such as rollability.

Fabrication and Oxidation Resistance of TiAl Matrix Coatings Reinforced with Silicide Precipitates Produced by Heat Treatment of Warm Sprayed Coatings

Abstract: Ti-Al-based intermetallics are promising candidates as coating materials for thermal protection systems in aerospace vehicles; they can operate just below the temperatures where ceramics are commonly used, and their main advantage is the fact that they are lighter than most other alloys, such as MCrAlY. Therefore, Ti-Al-Si alloy coatings with five compositions were manufactured by spraying pure Ti and Al-12 wt.% Si powders using warm spray process. Two-stage hot pressing at 600 and 1000 °C was applied to the deposits in order to obtain titanium aluminide intermetallic phases. The microstructure, chemical composition, and phase composition of the as-deposited and hot-pressed coatings were investigated using SEM, EDS, and XRD. Applying of hot pressing enabled the formation of dense coatings with porosity around 0.5% and hard Ti5(Si,Al)3 silicide precipitates. It was found that the Ti5(Si,Al)3 silicides existed in two types of morphologies, i.e., as large particles connected together and as small isolated particles dispersed in the matrix. Furthermore, the produced coatings exhibited good isothermal and cyclic oxidation resistance at a temperature of 750 °C for 100 h.

Effects of hot extrusion and heat treatment on microstructure and properties of industrial large-scale spray-deposited 7055 aluminum alloy

Abstract: The industrial large-scale 7055 aluminum alloy fabricated by spray forming technology was subjected to hot extrusion and heat treatment to achieve high strength and ductility. Microstructure of the as-deposited alloy indicates that higher density billets with equiaxed grains (20–40 μm) were fabricated rather than a typical dendritic microstructure of the as-cast alloy. The grains of the as-extruded alloy exhibit fibrous morphology, the original boundaries disappear and fined second phases with size about 0.5–5 μm distribute along with extrusion direction. Meanwhile, the defects could be eliminated by hot extrusion, which resulted in good strength as well as ductility. The ultimate tensile strength, yield strength and elongation of the as-extruded alloy are 345 MPa, 236 MPa and 18.5%, respectively. After heat treatment, the partial recrystallization is observed around the un-recrystallized grains and sub-grains. And the platelet/rod-shaped precipitates (MgZn2) show a uniform distribution in the matrix alloy. The alloy reaches the maximum tensile strength of 730 MPa after T6 temper treatment, associated with a fine precipitation (MgZn2). However, with further deepen aging degree (from T6 to T73 temper), the size of dominant precipitated phases (MgZn2) grows obviously, the grain boundary precipitates transform from continuous to individual ones and the width of precipitate free zone increases. The result shows that the alloy after T7X temper treatment exhibits higher electrical conductivity (>35 %IACS) and facture toughness (>25.6 MPa m1/2) although a 8%–17% reduction in strength compared with that at T6 temper.

Influence of carbon and chromium content and preform shape on the microstructure of spray formed steel deposits

Abstract: Given appropriate control of spray- and substrate-movement spray forming can be used to produce a variety of preforms. The microstructure obtained is governed by the thermal conditions during the spray forming process which can be influenced by the material properties, the atomization and deposition conditions. Within this study, the influence of carbon and chromium content as well as the preform shape on the microstructure is investigated. As master material unalloyed steels with low and high carbon content (SAE 1015, SAE W110 and SAE 52100) have been selected. Billets, plates and parts with defined geometry have been spray formed using different atomization gas pressures and comparatively examined by quantitative metallography and density measurement. It is found that the carbon content and the atomization gas pressure strongly influence the development of porosity. Also the state of the mould surface plays an important role. In contrast, the variation of preform shape and chromium content reveals no significant change.