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.

Densifying method for improving plasticity of spray-forming aluminum-silicon alloy

Abstract: The invention relates to a densifying method for improving plasticity of a spray-forming aluminum-silicon alloy. The densifying method comprises the following steps: 1) placing a spray-forming aluminum-silicon alloy ingot into a heating furnace to obtain semi-solid aluminum-silicon alloy; 2) putting the semi-solid aluminum-silicon alloy into the heating furnace to perform heat preservation processing; 3) performing pressure processing on the semi-solid aluminum-silicon alloy subjected to the heat preservation processing in a hydraulic press; 4) moving the semi-solid aluminum-silicon alloy subjected to the pressure processing in the step 3) out of the hydraulic press, and cooling. The densifying method has the beneficial effects that: after being subjected to the heating and heat preservation processing of the heating furnace, the pressure processing of the hydraulic press as well as cooling, the spray-forming aluminum-silicon alloy has product density of over 99%, and improves the density of the materials on the premise that the texture does not grow oversize, so that the microstructure and comprehensive performances of the alloy are remarkably improved.

On the texture of spray formed gamma titanium aluminide

Abstract: Spray forming is an attractive processing route for titanium aluminides that combines advantages both of ingot and powder metallurgy. Spray formed deposits were produced using the electrode induction melting gas atomization technique. The texture of a spray formed Ti–48.9 at.% Al deposit in the as-sprayed state and after isothermal forging as well as after isothermal forging and a subsequent stress relief heat treatment was analysed by means of neutron diffraction. The spray formed deposit was found to have a very weak 〈1 1 1〉-fibre texture with a maximum pole density of 1.12 multiples of random distribution. After isothermal forging of cylinders to 77% reduction at an initial strain rate of 2 × 10 −3 s −1 at 1150 °C, a band of orientations from 〈1 0 1〉 to 〈1 0 0〉 with a maximum close to 〈3 0 2〉 was found. A Zener–Hollomon parameter of 12.6 is estimated, which indicates that during isothermal forging dynamic recrystallization is governed by nucleation of new grains. A subsequent stress relief treatment at 1030 °C for 2 h caused additional grain growth, after which the maximum pole density is increased from 3.3 to 3.8 times random.

New Light-Weight Aluminium Alloys with High Mg2Si-Content by Spray Forming

Abstract: Aluminum alloys with high Mg2Si-content (>10 %) offer the possibility of a significant decrease in density and an increase in stiffness at the same time. But these alloys can hardly be produced in casting processes, due to an oxidation and a generation of pores by hydrogen solubility of the melt. Furthermore, the usual solidification rate is not sufficient for a fine microstructure morphology. A fine distribution of Mg2Si is possible by spray forming, where a coarsening of the particles can be avoided due to a higher solidification rate. Different aluminum alloys with high Mg2Si-content (>10 %) have successfully been produced by spray forming, extrusion and age hardening. Mg-excess as well as Si-excess has been investigated. An additional alloying with copper leads to a further increase in strength by the precipitation sequence of Al2Cu. The new light-weight aluminum alloys have been investigated regarding age hardening, physical and mechanical properties. Densities of 2.5-2.6 g/cm3 and Young´s modulus of approx. 80,000 MPa have been found. Microstructures were dense, homogeneous and of fine morphology. The yield strength of these alloys reached values of approx. 400 MPa after artificial aging, whereby only a slight decrease for the hot yield strength was observed up to a temperature of 200 °C. Applications of the new light-weight aluminum alloys can be expected where a reduced density together with a high hot yield strength would lead to a more compact design in high temperature environments, e.g. in combustion engines.

Method of preparing high strength magnesium sheet alloy

Abstract: The invention relates to technique for processing magnesium alloy, in particular to a method for preparing magnesium alloy planks with high strength and solves the problems that the rolling of the magnesium alloy planks is relatively difficult; the yield of the planks is low, etc. The rolling techniques of spray forming and deposited blank-rolling are used for preparing the high-strength magnesium alloy planks; oxygen with 0.01-0.03MPa is slowly injected into an atomization chamber after the completion of the atomization; over-spray powder of the magnesium alloy is then treated with passivation; then, deposited magnesium alloy ingots are directly and hotly rolled so as to prepare the magnesium alloy crystal grains with small size, even texture and relatively high mechanical property; the mechanical property of the magnesium alloy crystal grains can be further improved by the alloy treatment followed by the alloy rolling. Compared with the traditional preparation technique of the magnesium alloy planks, the technique of the invention has simple process and relatively low temperature of the alloy rolling, and can be applied to preparation of diversified magnesium alloy planks with the high strength.

Microstructural Characterisation by Scanning Electron Microscopy of Spray Formed Al/SiCp Matrix Composite

Abstract: The material used in this work was produced by spray forming AA7475 aluminium alloy and co-depositing silicon carbide particles (20% volume fraction). The spray formed composite billets were hot extruded into round bars. The microstructure was examined in the as received and heat treated (annealed, aged, and overaged) conditions by scanning electron microscopy. Scanning electron microscopy revealed an extensive Mg2Si phase precipitation at the Al/SiCp interface due probably to Mg segregation from the matrix to the interface, during the heat treatments.