The squeeze casting of aluminium alloys and composites
The squeeze casting of aluminium alloys and composites
It is obviously important to understand the effect of pressure on the solidification parameters if improvements in properties obtained by squeeze casting are to be explained and maximised. The changes in the primary and secondary dendrite arm spacing that occurred during the solidification of aluminium 4.5wt% copper alloy and an aluminium copper eutectic alloy, allowed the morphology affecting variables V,GL,GS,hc to be quantified. These morphology affecting variables were also measured directly by producing castings in a specially designed die set. This work allowed the dominant production variables influencing the mechanical properties to be found. It was found that an applied pressure of 80MPa produced fully dense castings and that the highest rate of heat extraction was obtained in castings solidified with 120MPa. This places a maximum on the load required for a particular casting to be characterised as a squeeze casting. It was also found that the dominant factor affecting the microstructural and mechanical properties of an aluminium 4.5wt% copper squeeze casting is the pouring temperature. The minimum pouring temperature producing the smallest grain size and the highest mechanical properties. When castings are solidified under pressure many parameters that have well defined values at atmospheric pressure change. Some of these changes can be calculated from simple theory; for example, the changes in the liquidus and solidus temperatures, diffusion coefficient and thermal conductivity can all be estimated. The changes in liquidus and solidus temperature allow phase diagrams to be drawn at any applied pressure. The aluminium silicon system was used and a phase diagram was constructed for an applied pressure of 120MPa, the diagram was verified experimentally by casting produced in a range of different aluminium silicon alloys. The squeeze casting process allows pore free metal matrix composites to be produced. In this work a range of 7010/Saffil M.M.C's. were produced and their mechanical properties evaluated. Properties measured included tensile, fatigue and fracture toughness.
University of Southampton
1990
Musson, Nicholas John
(1990)
The squeeze casting of aluminium alloys and composites.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
It is obviously important to understand the effect of pressure on the solidification parameters if improvements in properties obtained by squeeze casting are to be explained and maximised. The changes in the primary and secondary dendrite arm spacing that occurred during the solidification of aluminium 4.5wt% copper alloy and an aluminium copper eutectic alloy, allowed the morphology affecting variables V,GL,GS,hc to be quantified. These morphology affecting variables were also measured directly by producing castings in a specially designed die set. This work allowed the dominant production variables influencing the mechanical properties to be found. It was found that an applied pressure of 80MPa produced fully dense castings and that the highest rate of heat extraction was obtained in castings solidified with 120MPa. This places a maximum on the load required for a particular casting to be characterised as a squeeze casting. It was also found that the dominant factor affecting the microstructural and mechanical properties of an aluminium 4.5wt% copper squeeze casting is the pouring temperature. The minimum pouring temperature producing the smallest grain size and the highest mechanical properties. When castings are solidified under pressure many parameters that have well defined values at atmospheric pressure change. Some of these changes can be calculated from simple theory; for example, the changes in the liquidus and solidus temperatures, diffusion coefficient and thermal conductivity can all be estimated. The changes in liquidus and solidus temperature allow phase diagrams to be drawn at any applied pressure. The aluminium silicon system was used and a phase diagram was constructed for an applied pressure of 120MPa, the diagram was verified experimentally by casting produced in a range of different aluminium silicon alloys. The squeeze casting process allows pore free metal matrix composites to be produced. In this work a range of 7010/Saffil M.M.C's. were produced and their mechanical properties evaluated. Properties measured included tensile, fatigue and fracture toughness.
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Published date: 1990
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Local EPrints ID: 460700
URI: http://eprints.soton.ac.uk/id/eprint/460700
PURE UUID: 3c000d22-e658-47b0-a489-a97e8cb36bbb
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Date deposited: 04 Jul 2022 18:27
Last modified: 04 Jul 2022 18:27
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Author:
Nicholas John Musson
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