Squeeze cast aluminium reinforced with mold steel inserts

The bonding of a mild steel insert to an Al-7Si alloy during squeeze casting has been studied for a range of processing conditions. Assessment of the mild steel/Al-7Si alloy interface shear strength has been made with a push-out test, and the results have been correlated with microstructural observa...

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Bibliographic Details
Published in:Journal of materials science 1996-02, Vol.31 (3), p.589-602
Main Authors: Durrant, G, Gallerneault, M, Cantor, B
Format: Article
Language:English
Online Access:Get full text
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Summary:The bonding of a mild steel insert to an Al-7Si alloy during squeeze casting has been studied for a range of processing conditions. Assessment of the mild steel/Al-7Si alloy interface shear strength has been made with a push-out test, and the results have been correlated with microstructural observations and residual stress calculations. Uncoated inserts do not exhibit any significant reaction with Al-7Si because of rapid cooling of the melt during squeeze casting, giving a low interface shear strength of approx30 MPa. Preheating the inserts to 900 deg C slightly improves the interface shear strength to approx45 MPa, but reaction between the steel and Al-7Si is prevented by the formation of an Fe sub 3 O sub 4 magnetite layer on the steel surface. Inserts hot-dipped in molten Al-10Fe before squeeze casting have a much greater interface shear strength of approx110 MPa, with failure in the Al-7Si matrix rather than at the steel /Al-7Si interface. Inserts vacuum plasma spray coated with titanium have the greatest interface shear strength of approx130 MPa, without any interface reaction, because of mechanical keying of the rough splat-quenched Ti surface combined with high residual stresses in the Al-7Si matrix.
ISSN:0022-2461